This is one of about half of these shows I actually am familiar with and even still, at age 22, occasionally watch. Although my taste in TV leans more towards the dark, mature, adult themed dramas even I can't deny the genius of this show or the genius of Spongebob Squarepants. This theme song isn't the best theme song in the world (hence why it is at number 20) but even still, everytime I hear this tune I definitely like to sing along to it. This is one of very few children TV programs credited in this list, but if I had more space I would have probably also have liked to credit Fairly Odd Parents- although I haven't seen this TV program since I was about 12.
19. Seinfeld
I wish I could say this is one of the shows on this list that I actually watch, but alas, it is not. Even more embarrassingly I don't think i have ever even watched an episode despite regularly hearing that this may be the greatest sit-com of all time. This theme tune, though great enough to feature on this list (and great enough that despite not knowing the show at all well I am still familiar with this tune) is certainly not the best sit-com theme tune in the world (wait until number 1) but it certainly is iconic. Whenever I hear anyone mention Jerry Seinfeld on TV, the fist opening 5 seconds of this tune is generally hummed somewhere in the conversation. So, for the first 5 seconds, this theme tune deserves to be on this list.