I think you should carry Alpinestars line, Dainese, Motogp, Held gloves, Sidi line, and I wanna try the AXO line. I've heard good things about AXO, but I won't know until I get my suit in January. I hope not to crash test it.
Adam has put together a very complete list and I agree with his choices except for Dianese. I think the Dianese brand is too expensive and won't be worth trying to stock.
Offering Dianese would be a good choice but certainly not stocking anything they have. It could be an understanding that they are special order products for those willing to wait.
One last thing from a viewer's perspective. Please make your site easy to navigate and with good detailed pictures of the items. I hate trying to navigate a text website especially with today's web technology.
dnfab - yeah, I agree with the special order on the Dainese, I just included them because I know guys that swear by them and wont buy anything else. I wouldnt stock them either, as they are purchases few and far between.. :/