I've said before that I don't care one way or the other, as long as it is usable and readable without too much hassle or eyestrain.

That said, don't bother comparing forum features/performance between phpBB, SMF, vB, etc. They all have pretty much the same featureset and performance within a percentage point or two. I've run most of the "popular" ones at one point or another for various forums, and the differences are almost too small to worry over. The important thing is to choose the one you feel more comfortable with, and stick with it.

What I would like to have is a main index display mode which, by default, collapses everything that has no new posts. I know there is the "new posts" link, but meh. Just would like for it to come up with that by default.

Yeah, the RSS reader helps, but I don't really use it all that much.