At Target today I bought a Gerber EAB Pocket Knife. Instead of a traditional knife blade, it uses standard utility knife blades. But unlike a typical utility knife, the Gerber EAB is tiny, barely bigger than the blade itself, and extremely lightweight. This is a knife you could easily carry around in your pocket. It's made of matte gray stainless steel so it looks really nice too. Best of all, it's less than $11, which isn't much more than you'd pay for a regular utility knife.
(I found it in with the camping equipment, not in the tool department.)