I agree that it really doesn't matter that much which forum software you use but how much time and effort you want to put into it. I use invision board and not for any particular reason other than it was free at the time I decided I wanted to add a forum to my site. I don't know anything about PHP or CSS but I have been able to figure out how to add advertising and links, etc. It also uses CAPTCHA as an anti-spam measure which believe me is a very important feature as your forum grows.

I know I will bet flamed for this but in order to make it go along with the rest of my site and not spend much time I framed it. My main site is Coaching Drills, Information and Products For Youth Sports and the forum is Y-coach Message Board.