Some of the best theme music for television shows are simply allocated from other artists.  One such theme song is the intro to the Golden Girls.  Written by Andrew Gold whom I wouldn't even have known was a song writer other wise.  The song is great, very catchy and one that can be stuck in my head for a while.

The Wonder Years was one of my favorite shows growing up.  I loved seeing this show about Kevin's exploits through the 60's.  The theme song was a cover of a Beetles song by Joe Cocker and it rocked.  Have A Little Help From My Friends was a great Beatles song but Cocker own's it in his version as well.  In my mind the song and show are forever intertwined in my mind.  

Malcolm In The Middle's theme song was originally written for the series by They Might Be Giants specifically for the show.  So it differs from the previous two examples but I felt it was relevant.  Great show.  Great intro. The song really captures the feeling of being a kid and sets the tone for the series.

  

All of these themes will go down in history as some of the best.  Objectively, Malcolm in the Middle would win out because it was written for the show.  Subjectively, I enjoy the others just a bit more.