My favourite songs I heard first as TV themes:
Rembrants - I'll Be There, a.k.a. the theme from Friends: Friends was a little known American sit-com, you've probably never heard of it. The main basis of the programme was a great big "Will they? Won't they?" regarding the characters Rob and Rebecca (Or something similar, I forget). The theme was lovely and cheesy including the lyrics "You're still in bed at ten and work began at eight, you burnt your breakfast, so far things are going great." So profound, so true.
Remy Zero - Save Me, a.k.a. the theme from Smallville: The first series was great because of the "ooo, Superman as a teenager" factor, unfortunately it's gone downhill drastically since then. And, they've developed a nasty habit of stealing stories used in Buffy the Vampire Slayer, eg. Body swaps, invisibility, main character losing their powers, telepathy, witches, splitting a character into good side/bad side (The Buffy episode was way better, lots cleverer and much, much funnier) and so on. Plus it features the most boring and pointless "Will they? Won't they?" with Clark and Lana Lang. Pointless because we know how its gonna turn out. Stupid. The song's brilliant though. "Somebody Saaaave Me!". It sums it up quite nicely, ie. Save me from another godawful boring episode.
Phantom Planet - California a.k.a. the theme from The O.C. "Californyaaaaaaa, Californyaaaaaa, here we coooooooome". Another show featuring "Will they? Won't they?"'s Note the plural, Joss Schwartz must be really into his "WT?WT?"s. Personally I think Seth and Summer should be a "Will" and Ryan and Marissa a "Won't", largely because Ryan and Marissa bore the hell out of me and I want them to be miserable because of it. I think the O.C.'s completely shallow and vacuous but I love it and it's ridiculously funny. Though sometimes I'm not sure I'm laughing in the right places. eg. Lindsey: "Mom? What are you doing here?". hahaha! The theme makes me think of sunshine and beaches which can't be a bad thing.
Motor Ace - Death Defy a.k.a. the theme from The Secret Life of Us: "The Secret Life of What?" I hear you say. It was shown quite late on Channel 4 on - I think - Wednesday nights, possibly after Ally McBeal (no Vonda Sheppard isn't appearing in this list and for good reason - I'm not a girl). The show wasn't all that mega, it was just about a load of Australians going around getting drunk and having sex. Mind you, in all fairness are any TV shows about anything else? But the theme was ace (haha), and is what inspired me to make this list because I managed to track it down at last!