IPB is nice, but I haven't seen any software that compares to myBB. It really allows for more customization.
I think vBulletin is the best overall, but for small forums myBB is a good place to start.
Wordpress is more professional and has more sophisticated style,
Blogger seems more personal and fun.
Anyways that's how I see it. I don't know exactly which I'd choose, since I have only used Wordpress. :P