I would say take the shed, you'll find some use for it. I have contemplated this question also. I have a 20' x 11' basement shop, thats quickly loosing space. If you live in an area with a harsh winters (say the midwest), does it make sense to heat the shop through the week if you are only working in the shop on the weekends? Or do you run the heaters just when you are working in the shop? What kind of heaters are recommended (radient, wood stove, etc.)?
I marked out the one hole location, drilled a shallow 1/16" hole into the top. I then put a 1/16" bit through the hole in my template and into the hole I had just drilled. I lined up the template, and drilled a second hole, then put another bit through that. From then on, I worked entirely from the template. With two bits through the holes pinning the template in place, the other holes in the template would be precisely located (or so the theory goes) on a 4x4" grid.
Next is the shelf. Start with the 24x48" piece of MDF. Clamp this on top of the base, and pencil in the outside of the stretchers and the inside angle of the legs. Flip it over, pull out your trusty cutting guide, and cut it to width and to length. Cutting out the angles is simple, with a jig saw. It's not much work with a hand saw. If you took enough care with supporting blocks and stops, you could probably do it with a circular saw. Since I did have a jig saw, I used it.

As simple as its elements are, the workbench is more than a tabletop with legs, a well, and a few holes. Virtually everything in the workshop comes to rest on the bench at some point, even if only between operations at other stations. Planning and layout, cutting and shaping, assembling and finishing–all can be, and often are, performed on the benchtop. The better the design, and the better suited its size and configuration to your labors, the more efficient a tool it will be.
Not sure about Midwest but I have a 24 x 14 Game rm attached to my shop and I put a small window unit/heat pump in the wall. It stays comfortable all year round. It get really hot here and we had a several day in the 20's this winter but it's insulated well. That might not be as cold or as hot as in some places but the unit I haze does not run that often and has a low cost rating. I'm planning on putting a larger unit in the shop area even though I do like to work with the garage door open. The door is insulated so I can run A/c in there. Just my .02.
We are especially proud of Post Woodworking’s Brunswick style shed. It has all the rugged features and simple, beautiful mystique of a Maine coastline. Natural-wood siding options, in pine or cedar, offer a rustic aesthetic. Or, choose a vinyl color that complements our home. Once inside the Brunswick, its unique, two-sided sloped roof maximizes headroom, making space for you to better maneuver a rake. Black architectural hinges and hardware lend distinguished contrast and quality to this basic but appealing storage solution.