wheel - 4:18 am on Dec 13, 2004 (gmt 0) (I'm currently migrating from phpbb to one of the other two I mentioned).
I just researched this topic myself and came up with:
- phpBB if you're looking for free software. Expect somewhat frequent updates, there seems to be a lot of security updates. However, it is a very popular program so there are lots of hacks and mods for it.
- for low cost paid software, vbulletin or invision power board are both a couple of hundred $'s and seem to be the next step up.
(I'm currently migrating from phpbb to one of the other two I mentioned).