I use mostly Craftsman - can't beat the warranty and availability, plus I used to work @ Sears while in college.
I have a Makita cordless drill/driver with a 10" flexible extension that I use to speed fasteners on & off with (a trick I learned from a professional mechanic friend) and I can't imagine working on a car without it. The flex extension is like a thick piece of wire rope with 3/8" drive on both ends. It is Armstrong brand; I bought one from Sears in 1/4" drive size and it is much too stiff and cannot handle much torque without wrapping up on itself.
My latest tool quest is for a cantilever tool box to carry around my most used tools. I saw this one
at Griot's Garage but I think a bigger box would be better.