Illmatic - Nas
The College Dropout/Late Registration/Graduation - Kanye West
The Low End Theory/Midnight Marauders - A Tribe Called Quest
Enter The Wu-Tang Clan 36 Chambers - Wu-Tang Clan
good kid, m.A.A.d city - Kendrick Lamar
These are albums that are widely known and are for the most part critically acclaimed. Some people I know who aren't into hiphop that much like some of these albums
Food & Liquor - Lupe Fiasco
Death Certificate - Ice Cube
Black Bastard - KMD
Tha Carter III - Lil Wayne
Only Built 4 Cuban Lynx - Raekwon
Liquid Swords - GZA
And these are personal favorites that eased me into the genre.