@Joe: Why? It doesn't really matter to me whether or not you use it. At one point, I would have been able to explain why it's faster off the top of my head, but I've forgotten, and it'd be just as much work for you to look it up as me.
@Ergot: I just go ahead and make the whole deal reiserfs unless I'm building a server where there's some benefit to splitting the drive up. Also, Gentoo FTW! What USE flags do you use? ^_^