Show up naked.
Bring food.
Ok, seriously. Maybe he'd find use in an air compressor? It certainly won't help with installing a stereo, but it can make quicker work of some mechanical jobs. Check out the Craftsman sales at Sears. They often have decent sales on some of their air compressors where they also come with some air tools. Join the Craftsman club for an extra 10% off on a Craftsman weekend.
In fact, if you ever want to buy Craftsman tools, join the Craftsman club. I'd recommend Craftsman over Snap-On simply because of cost, and Craftsman tools are good. Not ALL Craftsman tools are lifetime warranty, but most are.
I dunno what this guy likes so it's hard to recommend, but I agree with others who have stated perhaps it's a good idea to get him something different, maybe totally off the wall that he wouldn't expect. For those suggestions, I'd have to know him.....
b