Better yet, read this:
http://www.sonicyouth.com/gossip/showthread.php?t=25363
I'd get PENULTIMATE GALACTIC BORDELLO or ELECTRIC HEAVYLAND. They're all good, though, to an extent. I have downloaded about 40 of em and uhh... I don't break em out too often but on acid they rule. I like the side projects/solo projects better usually. For the most part, if you get just a few albums by them, you've gotten them all, in a way. I mean, a lot of their stuff is very very samey.