PowerBBS

Oh, you meant internet BBs... Snitz is nice, a tad on the slow side, and the older versions (like the one the EVE:TSG forums use) don't have [ url ] tag support.
Example:
www.eve-online.com Infopop's Ultimate Bulletin Board is very popular, even HLP uses it

. It's a pretty basic software, which has most of it's fineties internally (I used to have one). Reliable, but a systems resource hogger.
Example: You're looking at one.
Jelsoft's vBulletin is a very nice software. Big on resources and rather prone to crashes on Internet Explorer, it nevertheless holds the crown in features and ease of use. Unless you're willing to get a dozen hacks for UBB.
Example:
www.spacebattles.com ,
www.volitionwatch.com IkonBoard is almost a UBB copy, except it's free and doesn't use nearly as much systems resources. It misses some of the features of UBB too.
Example:
www.hyppyportti.net , but that's down at the moment. Don't know any other IB users.
PHPBB is, as the name states, PHP based bulletin board software. It also is free, but it's also very easy to use, configure and has all the features a basic BB needs. I've got one at the moment. + I've heard it's VERY easy on systems resources because it's based in PHP.
Example: I'd give you mine, but it's still classified

That's about all I know.