With the proliferation of blogs, some have thought that forums were dead or on a down hill slide. Personally, I feel that there will always be a place for forums.
I watch some important forums myself and am a regular poster. One of the best I like for my own industry is Webmaster World. I can pick up tips, keep up-to-date on topics, and sometimes even hear of an issue there first.
But forums are not for everyone! I do not recommend the addition of a forum to the typical business owners website, in that case I recommend a blog. The reason for this is that unless a forum is trafficked, has a moderator, and lots of activity, it simply cannot be sustained. A forum with no activity may actually be a liability for you. For smaller websites and business owners the one way action of blogging is a much better match.
So from my point of view, forums have their place and blogs do as well. What forums are you watching and lurking in?