There's always Star Trekkin' by The Firm.
If you haven't heard it (or, heaven forbid, haven't seen the video)...
You're very lucky.
As for STAR TREK: CHURCHILL, my TOS era game (and assuming I can badger the people whose house the game is played in to actually prise the Tenacious D (or B, or something) or Rammstein albums out of the Hi-Fi. Trying to run a game while some German band is shouting stuff I can't understand in a really deep voice is only just preferable to running a game to the musical accompanyment of Limp sodding Biscuit) I use the live accoustic version on the single of Superman (It's not easy) by Five For Fighting as previously mentioned by someone in this thread (I prefer it to the studio version).
I wouldn't mind using the end title music from ENTERPRISE since I quite like that.