Oh please. MotoGP takes this prize hands down.
Don't leave out the 2-wheel racing.
I agree, a lot of these sports need some diversity...and it surprises me that the teams and race organizations don't push harder for it...i mean, look at the press and interest Danica Patrick has generated for IndyCar, an admittedly struggling race series. From a pure marketing perspective, a little "controversy" (if diversity could be called that) is ratings gold.
i know it might be a bit far for you, but you would be in seventh heaven if you're a biker.....
http://www.iomtt.com/News.aspx
I've been several times, it's the dogs bollocks