+1 on the full GB kit. Includes frame sliders, case protection for both sides, front and rear axles plus toe guard for the rear sprocket. Comes to under $400 (I think) which I'm sure is less than most peoples' insurance deductible.
I look at this stuff more as "tip over" protection as opposed to actual crash protection. you never know what's going to happen if you become seperated from your bike at speed, but in the driveway, parking lot or pits this stuff is sure to protect the tank, frame, and engine cases from costly and unsightly damage.
In the long run it's cheap insurance.