I voted for "Baba O'Riley" myself because it is the one theme song I can never get out of my head. Like, I'll be at the mall and just burst into song!
My favorite is NY's Baba O'Riley. I've always thought CSI's Who Are You is catchy but somehow Baba is catchier. ETA: I'm listening to Who Are You right now and I'm itching to call it my favorite too! So uh, I'll give it a tie.
CSI:NY's Theme (Teenage Wasteland) when it comes on every Wednesday night, I crank up the volume on my tv, it's awesome!
I am not old enough to remember when any of the Who songs were recorded (i would think '70's? I was born in the '80's. My dad listened to Teenage Wasteland when he was a teenager though, that song has to be at least 30 years old!
who are you is great, but won't get fooled and baba o'reilly are great too. waaaaaaah i can't choose!