I wanted something about 4' x 3'. I looked at a couple, and the Suncast GS4000 seemed to fit the bill. I special ordered it from Lowes. I think it was around $219 or something, pretty reasonable. You can put shelving in it, and it snaps together very easily.
The patio area I put it slopes away from the house 1" per 48". So I ended up making some big shims out of 4x4's and mounted the base of the shed to the 4x4's and piece of plywood. Sawzall didn't work too well cutting the 4x4. I needed a bandsaw, but just made two cuts on either side with a skillsaw.
I also decided to bolt the shed to the wall since we get those pesky hurricanes every now and then in Houston. I've got four 1/2" lag bolts holding the thing into the wall. I've got a 2x4 sandwiched in there as a spacer which will let air movement behind it, and keep moisture from getting out of hand.
Anyway, here's some pictures. I need to make some more shelving for it. It took much more time to build the base and secure it to the wall then it did to actually put the shed together
http://main.experiencetherave.com/images/storageshed/
It's really helped get some of the clutter out of the garage. I can actually see my walls.