Some of the ones I like...
MG/HS Hour
Big Wheels (of course, Woolery Wheel and early Sajak NBC Wheel theme)
Split Second (original....between this and Big Wheels, I think it's an unwritten rule...BONGOS = INSTANT GREAT SONG. For those of you from the NY area, I also present WPIX's Channel 11 Film Festival theme as another example)
Whew! (would that I could find a clean copy of this)
Hitman (ditto)
Password Plus
Password Plus "going to Alphabetics" theme (the song they usually play as a commercial outro when a match is finished or, yes, when the players walk over to the Alphabetics area)
Press Your Luck
Tuning Up ('70s Pyramids, both the show edit and the long version on the GSN2 CD)
'80s Pyramids (Tuning Up Again?)
100 Mexicanos Dijeron (the more FF-flavored first theme)
Card Sharks (all but, of course, the CASINO theme in 2001)
The Barry-Enright Big Three ala Hidey
Break the Bank '76 (show edit(s))
Random observation: though I like the High Rollers '78 theme, was it just me or did the NBC H-Q Two (HR '78 and Las Vegas Gambit) have themes where the musical piece building up to the title appearing were kind of more exciting than the rest of the song? (I mean the music that plays when the animated dice appear with either the numbers of "1978" or the "HR" logos, and the music when the word "Gambit" forms)
Another thought: which GS themes spun off into the best musical cues (for wins, bonus game transitions, commercial outros, etc)? I already mentioned the PW+ "going to Alphabetics" music, and I liked the front game winning jingle as well. I also liked that part of the CS78 theme used for revealing the Money Cards board.