Thanks for your comments. I suspected the 70-200 f2.8 would be the ideal but the price is a bit
. I usually use a 35mm f1.8 for most of my photography and love shooting at around f1.8-2.8 but it's obviously too short for RC.
My tele lens is a 55-200 cheapy, great photos from such a cheap lens but not fast enough for indoors.
I also shoot karate at competitions occasionally and need a fast lens for that, but the 35mm is ok as long as I can get close to the mat. Longer would be better for though as I could blur the background out a bit more and not have to risk getting kicked!!!
I've recently upgraded from a D40 to a D7000 and I've yet to see how it's faster ISO performs. The D40 was struggling at times to get a decent shutter speed and have acceptable noise, even at f1.8. Having the in body focus motor has opened up a heap of older cheaper lenses for me to look at as well.
Might look into renting a 70-200 for the next karate comp. and see how it fairs.