Well, for me, TPiR '72's theme is number one. Best theme of all time, you just can't help but get excited and/or sing along. I probably hum it two times a day, at least.
Nickelodeon's Double Dare ('88-93) probably had the best music of any kid game show, and the obstacle course cue is a perfect example of how Edd Kalehoff felt the tension and excitement of those kids running around. Unfortunately, it sounds to me now that I have Nick GaS on digital cable that the cues from Finder's Keepers could've been rejected DD ones.
Supermarket Sweep - Memorable melody, fit the show perfectly, I can hum along to it.
The current Jeopardy! and Wheel themes are quite good, IMO. They're better than the mid 90's Wheel big band and J! bongofied versions. I can see why some of you would think the current arrangement for Wheel has no structure, because it doesn't have that "stick in your brain and repeat throughout the day" feel to it.
Jeopardy '78 - Probably one of the most underrated catchy, laid back themes of the genre. I wish Merv would release it on an album to hear the whole thing.
MG '7X - Has a nice groove to it, and although it's a bit heavy on the synths in some parts, it's really good.
Least favorites - Shop 'Till You Drop, Pictionary '97, Showoffs, Mindreaders, Better Sex, All Star Blitz. Generic GS music that got annoying for me after repeated listenings.
James