If you could only buy 10 rap albums ever, these are the ones I'd recommend.
"The Chronic" - Dr. Dre
"Chronic 2001" - Dr. Dre
"NWA Legacy Vol 1" - NWA & various related artists
"Enter the Wu-Tang: 36 Chambers" - Wu-Tang Clan
"Wu-Tang Forever" - Wu-Tang Clan
"Watermelon, Chicken, & Gritz" - Nappy Roots
"Eternal E" - Eazy E
"Devil Without a Cause" - Kid Rock (some rock influence, but Kid started as a rapper and believe it or not, toured with Ice Cube in the early 90's)
"The Marshall Mathers LP" - Eminem
"Doggystyle" - Snoop Doggy Dogg
"The Chronic" - Dr. Dre
"Chronic 2001" - Dr. Dre
"NWA Legacy Vol 1" - NWA & various related artists
"Enter the Wu-Tang: 36 Chambers" - Wu-Tang Clan
"Wu-Tang Forever" - Wu-Tang Clan
"Watermelon, Chicken, & Gritz" - Nappy Roots
"Eternal E" - Eazy E
"Devil Without a Cause" - Kid Rock (some rock influence, but Kid started as a rapper and believe it or not, toured with Ice Cube in the early 90's)
"The Marshall Mathers LP" - Eminem
"Doggystyle" - Snoop Doggy Dogg