I couldn't imagine a "thrash elitist" picking Obsessed by Cruelty as the best Sodom album... it's barely a thrash album. That being said, I take back my recommendations and say start from the beginning with all those bands. IMO, it's the best way to discover any band. Listen to the evolution and you'll end up appreciating the older albums more and understanding why the later albums sound like they do.
I love inside jokes, I'd love to be a part of one some day.