You need to drop (return or cancel the order) the FX-6100 and at least get the FX-6300. It has architectural improvements along with a higher clockspeed, which will give you more performance in TF2.

You should have took his original advice. While it isn't a terrible build, it could be tweaked to give you, personally, something better. This would have been more suited for you:

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD FX-6300 3.5GHz 6-Core Processor ($118.99 @ Amazon)
Motherboard: Gigabyte GA-970A-D3P ATX AM3+/AM3 Motherboard ($76.99 @ Newegg)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory ($58.65 @ Newegg)
Video Card: PowerColor Radeon HD 7770 GHz Edition 1GB Video Card ($79.99 @ Newegg)
Case: Rosewill Challenger-U3 ATX Mid Tower Case ($49.99 @ Newegg)
Power Supply: Corsair Builder 430W 80 PLUS Certified ATX12V Power Supply ($42.98 @ Newegg)
Monitor: Asus VG248QE 144Hz 24.0" Monitor ($239.99 @ Newegg)
Total: $667.58
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-08-31 17:39 EDT-0400)

I ordered the Stealth and some mouse feet last week. Put the mouse feet in a separate order with the cheapest shipping option. Shipping will only be an extra 50 cents if you choose the cheap method. Since I placed both of my orders back to back they actually combined the feet and pad into the same box so they arrived at the same time.

Motherboard should be fine.

You can get the FX-8320 instead of the 8350. Should overclock to 8350 speeds and beyond easily.

The 650W Rosewill Hive is on sale. Very good deal, cheaper than the 550W. Pick it up.
http://pcpartpicker.com/part/rosewill-power-supply-hive650

Consider this case for an upgrade. A bit larger and roomier on the interior.
http://pcpartpicker.com/part/xigmatek-case-cccae37bsu02

And if you need to cut the price, you can drop the video card down to a 650 Ti BOOST.

Stick with the 4770K. TF2 is so CPU intensive on high settings, and the hyperthreading will help you tremendously when streaming.

While the 7970 performs great for that price (plus those games), Nvidia cards offer Lightboost for your monitor which would be a competitive advantage. The 770 is a pretty good value; recommend that rather than the 670 or 680.

Everything else can be changed to accommodate personal taste and budget.

After market cooling is basically necessary. Intel's stock coolers are garbage. The delta between stock cooling and a $30 cooler is huge. The delta between $30 coolers and more expensive cooling isn't as large, so here you can fine tune your budget in very granular amounts. In other words, pay a little more and get a little more performance step by step.

Cases you could spend as little as $50 and still get a great case. Mostly determine your style. There are several great options and I recommend you look at Corsair, Fractal Design, Cooler Master, NZXT, Rosewill, Lian Li brands. Although as you get cheaper you'll lose out on size and a few features - like fan controllers. Size isn't that big of an issue; a good sized mid tower provides plenty of room when using a single video card. The case you picked offers a lot, but you can cut costs here if you can live without a few things.

You could knock a little bit off the power supply if necessary, but there isn't a better power supply for less than the Corsair HX650. It's a very good price right now. I'd stick with that.

I tweaked your latest build.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD FX-6300 3.5GHz 6-Core Processor ($119.99 @ Newegg)
Motherboard: Asus M5A97 LE R2.0 ATX AM3+ Motherboard ($68.99 @ Newegg)
Memory: Patriot Viper 3 8GB (2 x 4GB) DDR3-1600 Memory ($55.99 @ NCIX US)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($64.99 @ Newegg)
Video Card: PNY GeForce GTX 650 Ti Boost 2GB Video Card ($119.99 @ Newegg)
Case: Rosewill CHALLENGER ATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: Corsair Builder 500W 80 PLUS Certified ATX12V Power Supply ($29.99 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($14.98 @ Outlet PC)
Monitor: Asus VG23AH 23.0" Monitor ($179.99 @ Newegg)
Total: $689.90
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-06-04 18:37 EDT-0400)

-Dropped the CPU cooler to cut costs.

-Upgraded to a faster CPU.

-Swapped to a cheaper, but almost equivalent, motherboard. If you're looking to do small overclocking, this board is actually better for that than the MSI board. If you want to do mild to large overclocking (4.3 Ghz or faster), it's recommended to spend $100 or more for a better motherboard.

-Upgraded to 8GB of RAM.

-Swapped the HDD to a Western Digital. Slightly cheaper and it also had a combo deal with the Rosewill Challenger.

-Swapped the HAF 912 to the Challenger. They both have basically identical features; styles are just different. Challenger ends up being cheaper which is the main reason for swapping.

-Upgraded to a faster video card. It's cheaper after the large rebate, too.

-Finally, upgraded the monitor. While you lose an inch of size, the VG23AH is an IPS panel so it will have much better colors than the TN panel. Also this monitor can be clocked to 72-76 Hz.

By making all these tweaks I was able to cut your cost down, but you will have to wait for your money to come back with a bigger investment in mail-in-rebates. Now if you would like an aftermarket cooler, these are the best options for the price:

http://pcpartpicker.com/part/zalman-cpu-cooler-cnps10xoptima - $13 after rebate
http://pcpartpicker.com/part/cooler-master-cpu-cooler-rrb10212pg1 - $20 after rebate

If you're buying soon, make up your mind soon. The deal on the FX-6300 ends tomorrow, and some of these other deals may not last.

You'll need a good power supply to overclock the AMD chip. 500W or less won't cut it.

Don't get a Thermaltake power supply.

http://pcpartpicker.com/part/corsair-power-supply-cx500m
http://pcpartpicker.com/part/rosewill-power-supply-hive550
http://pcpartpicker.com/part/xfx-power-supply-p1550sxxb9

Yeah, your video card will slide in without any problems.

You can get more for the same price by building yourself.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD FX-8320 3.5GHz 8-Core Processor ($163.98 @ SuperBiiz)
Motherboard: Asus M5A78L-M/USB3 Micro ATX AM3+ Motherboard ($69.99 @ Newegg)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1600 Memory ($51.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($62.98 @ Outlet PC)
Case: Fractal Design Core 1000 USB 3.0 MicroATX Mid Tower Case ($29.99 @ Newegg)
Power Supply: Corsair CX 500W 80 PLUS Bronze Certified ATX12V Power Supply ($34.99 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($14.99 @ Newegg)
Operating System: Microsoft Windows 8 (OEM) (64-bit) ($89.98 @ Outlet PC)
Total: $518.89
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-05-28 01:05 EDT-0400)

+much faster processor
+much better power supply
+better motherboard

The Intel alternative:
CPU: http://pcpartpicker.com/part/intel-cpu-bx80637i53350p
Motherboard: http://pcpartpicker.com/part/msi-motherboard-b75map45

Get a better power supply. That one is basically a 450W unit being sold as a 550W unit. It would be fine if he doesn't plan to overclock, but judging by the parts you chose it looks like overclocking is a consideration and thus I doubt that power supply can handle it.

Unfortunate part is that power supplies seem to be more expensive in Canada than the US. But a good power supply will go a long way so it's worth it to spend the money on a reputable brand/model.

The best deal I've seen on various sites is this 550W Corsair Enthusiast, $30 off. Pick this up before it runs out of stock.
http://www.canadacomputers.com/product_info.php?cPath=33_442&item_id=015941

The Acer will be the fastest. GPUs are basically the same performance. CPUs are drastically different.

CORSAIR CX430M 430W ATX12V v2.3 80 PLUS BRONZE Certified Modular Active PFC Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139049

More than enough power for this kind of build.

My suggestion would be to first upgrade the video card and power supply. See how that upgrade treats you and if you are satisfied with the performance.

If you aren't, then you can look into overclocking so long as you have a good motherboard and RAM. If you have a board that cost less than $100, overclocking probably isn't an option as you risk damaging the board. But if overclocking is an option, you should be able to boost your processor to at least 3.5 GHz and also boost the northbridge speed from 2 GHz to at least 2.6 GHz. Of course you'll want a decent heatsink to do this, so if you don't have one then get one and make sure it's compatible with newer sockets as well.

Adding/upgrading more RAM would also be an option too if you have DDR3. If you have DDR2 it's not worth it.

If after all of that you still aren't satisfied, then upgrade to a new CPU/Motherboard.

Oh and and SSD will be a great addition to your current build or a new build.

Since the computer has issues, and since it doesn't make sense investing in another 1366 motherboard, you should probably just look to sell everything. The most likely culprit for your problems is the motherboard anyway. Your processor can still fetch a nice sum of money for people looking to upgrade their own 1366 rigs, and you can then upgrade to an i7 3930k which will be faster and on a newer platform.

The other likely causes of the issue is the power supply or RAM. Perhaps it's not quite in spec. You probably should have RMA'd the motherboard whenever you found a problem. It probably has a 3 year warranty on it, so you may still have a chance to do so but time is running out.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-3350P 3.1GHz Quad-Core Processor ($169.99 @ Newegg)
Motherboard: ASRock Z75 Pro3 ATX LGA1155 Motherboard ($76.99 @ Newegg)
Memory: Crucial Ballistix Sport 8GB (2 x 4GB) DDR3-1600 Memory ($47.20 @ Newegg)
Storage: Toshiba 1TB 3.5" 7200RPM Internal Hard Drive ($69.99 @ Newegg)
Video Card: MSI GeForce GTX 650 Ti 1GB Video Card ($94.99 @ Newegg)
Case: Rosewill REDBONE U3 ATX Mid Tower Case ($29.99 @ Newegg)
Power Supply: Corsair CX 430W 80 PLUS Bronze Certified ATX12V Power Supply ($44.99 @ Newegg)
Optical Drive: LG GH24NS95 DVD/CD Writer ($17.99 @ Newegg)
Operating System: Microsoft Windows 8 Full (64-bit) ($99.99 @ Newegg)
Total: $652.12
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-04-26 19:52 EDT-0400)

Go to Microcenter and get an i5 3570k and motherboard combo. Should be about the same price as the CPU/Mobo listed above.

Excluding Windows from the budget will allow you to also bump the video card up to a GTX 660 and get a better case.