You're a more hardcore metal fan, so I'd recommend getting their first two albums first. It takes a while to really absorb them, though. I prefer Altars of Madness to Blessed are the Sick, but they're both very good, though inaccessible to the inexperienced.
Oh, and Covenant has Angel of Disease, the best Morbid Angel song ever. Hell, even Korn found the need to rip off one of its riffs. Their song Ball Tongue stole the chorus riff. Ytmnd is down, but the "riff rip-off" series has it.
http://youtube.com/watch?v=eA0U1KZP4VQBy the way, Angel of Disease is actually one of the older Morbid Angel songs, going back to their mid 80's era. The fact that Korn's riff only appeared after the song was finally put on an album and heard by the masses shows what trend whores Korn are.