I'm a big rider and small-time racer, so I try and keep up on my Moto GP. As mentioned though the coverage is horrible. I used to order the Speed channel just to watch it, but decided $10/mo for the "package" it was available on was crap, so I cancelled it. I try to find bars that show the races but there aren't too many.
Much more exciting to watch than Formula 1 I think. The races are short and there is a lot of passing. Anyone who can get ahead of Valentino Rossi is racing like a monster, which is always fun to watch.
Edit: Crashes, aka 'dismounts', are better than a stupid car crash anyday