I love both F1 and Sports cars. F1 is a spectacle, and awesome, Sports cars are probably better racing.
I agree about Nascar. Sticker change=change of automaker. Basically Spec cars. I tolerate them on the few road course races that they run.
If it comes down to football or Nascar, I'll watch Nascar, at least it's motorsports.
Roundy-round just doesn't do it for me, except for Sprint cars! Those things are bad ass. 1200hp in 1200 pound cars, those guys are real men!