Did you ever wonder why you've played a lot of Street Fighter II, but never played the original game? Well it actually existed, and it stayed mostly in the arcades for years. You mainly controlled Ryu, and fought with a more basic combat set-up. There was apparently a 2 player mode as well.
Capcom eventually ported the game to the TurboGrafx-16. The version was known as Fighting Street. It's currently available on the Wii's Virtual Console.
I hear the TG-16 version is pretty decent, but the game has apparently aged quite a bit. I still want to try it out though.
From all the opinions I've heard of the original game, it's not a surprise that the series didn't take off into stardom until the excellent Street Fighter II.