I'm an aircraft mechanic for a major airline out here in CA. I've done pretty well with craftsman boxes, one thing you gotta remember, all the toolbox has to do is hold the tools, the more you save on the box, the more you getta spend on tools and car goodies.
First, you're gonna need a good set of wrenches, a good socket set, a good set of pliers, and a good set of screwdrivers. These are the tools you will use the most, so you need them strong and well made. When you start getting into the specialty stuff you gotta look at what it's gonna be used for. For example, stubby wrenches, you'll never get enough torque on a stubby to break it. I got mine from harbor freight, they do exactly what I need em to do, and if I ever need to, it won't bother me one little bit to take them to a grinder and modify them.
Just remember, it's more fun to show off with your car than your toolbox.
P.S. A four dollar hammer from harbor freight works just as well as a fifty dollar hammer from snap on...