[color=#000000
ost_uid0]UBBThreads (see TrekBBS or Terran) seems to be a good one, so far as I know anything about these things. It also happens to be the company Charles works for.
VBulletin also looks and functions quite nicely (see
TrollKingdom.com,
StraightDope.com and/or
SubSpaceBBS.com for examples.) It also seems to be favored somewhat among programming-geek types over UBB.
S'all I know.[/color
ost_uid0]