I honestly am not sure what I'd recommend to branch out. Obviously more west coast stuff is in order (Doggystyle by Snoop Dogg, for example). Maybe some older New York stuff since you like 50 and Jay?
In that case I'd recommend the following.
Nas - Illmatic
Wu-Tang Clan - Enter the Wu-Tang (36 Chambers)
Jay Z - Reasonable Doubt (if you haven't heard this one)
The Notorious BIG - Ready to Die