Here's a pretty interesting way to always have certain essential tools on hand: Technical apparel company 686 Enterprises offers this tool belt, which isn't meant to hang tools from, but contains its own.
The dual prongs have flathead and Philips-head screwdriver tips, the buckle operates as a bottle opener, and the metal loop has three different sizes of socket heads cut into them.
You can remove the tools without taking the belt off, though you will of course have to unfasten it. At first I thought that would be a problem since your pants would sag, but now I realize it's the perfect excuse to display Plumber's Crack while you bend over to fix whatever needs fixing.