Santa Baby, though I might be personally biased against it because I had to sing it as the result of losing a bet I made that one of my older games would never achieve anything.
I really really hate that 'FIRST PACIFIC, THAT'S TERRIFIC' song that plays in an awfully obnoxious Australian advert.
I seem to have a good level of detection for when a song is going to be bad, going by what I've heard in here, it's probably to my benefit that I've stuck to enjoying video game music and things WITHOUT LYRICS.
Only one or two songs with Lyrics that I like and that I think are better with lyrics rather than just being instrumental.