Ha ha I'm a gay fag boy!
Seriously though, from all the answers in this thread you'll have to do whatever the fuck you like! PERSONALLY I'd say start with "Scream Bloody Gore", then "Leprsoy" - work your way from the early stuff onwards. In my opinion, (and I'm in the VAST minority here) Death only got worse over the years. From the basic, but sheer genius of Leprosy ("Pull The Plug" "Open Casket" anyone?) and "Human" to the overblown and overworked "Sound Of Perseverance", Chuck was at his best when he kept it simple.
Leprosy, Human and SH are the ones I'd go for first. Although their cover of "Painkiller" turned up REALLY FUCKIN' LOUD is utterly fantastic!