It's time for me to come clean.
A couple months ago, I left my digital SLR on the roof of the car and drove away without it. There was a thumping noise as $1,000 worth of camera equipment bounced off the trunk en route to the road. It was in a bag, but even so I got lucky: the only damage was a lens cap bashed into the UV filter.
Which is why the Camera Armor product caught my eye. It's a rubberized skin for your SLR body, including a stretchy protector that fits around the rim of lenses up to 85mm in diameter and a transparent polycarbonate shield to protect the screen.
Of course, the new skin means your camera will be even bulkier, and it's only available for Canon 30D and Nikon D70 cameras. But for $50, it's probably worth considering if you're rough on your camera--or too distracted to put it on the inside of the car.