Onemoretime has a good thought regarding the work bench space. I once had a garage 24' deep and it was a little tight in the front with a work bench up there and a full size pick up in a bay. Plenty of room for a Corvette. Once you build it you will always want more space. If you are going to be building car sized projects I would go a little deeper - but that is just me. I like a lot of space.