Ken Levine got in on the TV theme song meme, and I must add my two cents, given that I come from the younger generation and that I'm not, I hope, a moron. My one addition is that I'm going to include TV theme music, which sometimes isn't a song but just absolute instrumental sound. (Keep in mind, this isn't exclusively TV score music, so the sounds from "Lost" won't be on this list.)
Alas, my 10 picks for TV music openers:
1. Magnum, P.I.
2. The Sopranos
3. Curb Your Enthusiasm (not available online, but this bad ringtone is funny)
4. Diff'rent Strokes
5. Knight Rider
6. Nip/Tuck
7. Love Boat
8. Bewitched
9. Baretta
10. The Jeffersons
Honorable Mention: Taxi, Welcome Back Kotter, Moonlighting, Northern Exposure, Adam-12 (How could I resist?), CHiPs