I'm pretty sure this hasn't been mentioned in teh previous posts (altho, I was just skimming), but
The Horse by A Wilhelm Scream off their album Career Suicide has a truly bitchin bass line. It's solo'd during the opening vocals, and then mimicked by the guitars in the middle of the song.
i'll second this. hell, pretty much every song on career suicide has amazing basswork - brian is a fucking machine! they played a coupla new songs when i saw them last month, and one of them featured a mental bass intro.