All good info, use it wisely. First off, spend the time to figure out the size of the building that will work out best, and by tht I mean by the way it looks and is in agreement with your wife. Remember: Happy Life, Happy Life . Work within your means and you'll never regret it, it can always bigger, or taller, or better, especially to others. Unless you buy into the bigger thr better, it's not always true, If you own a 6'' jointer, you'll eventully find a job that needs an 8", and then when you own the 8' you'll eventully find a job that needs a 10", and so on and so forth. Figure out what you'll really need ahead of time and fit the shop to those items.
If possible, take the time to get the electric, cable, phone, plumbing (?), insulation, compressed air lines, dust collection and hvac set up before moving in. If affordable, radiant floor heating is the best and most comfortable. Also try the have at least one 240v outlet in the middle of the floor.
For 90% of the people, and the work that they do, a 24'x36' shop with ceilings that are tall enough to stand up 8' sheets of plywood, and not hit lights, is more than big enough. Even including wood storage in that, it should be enough room and any thing else is gravy. I have a 32' x 40' pole barn with 12' ceilings as a shop and even though it has enough room, it also has it's problems, a/c and heating (especially with the high ceilings) being a major one. When I first started out it was all woodshop , but recently I've used only one side (22x32) for the woodworking and the other side is used for automotive and metal working. In the woodworking side I have a bathroom, and the following equipment: 10" Jet cabinet saw w/side table, router table, 15" PM planer, 8" jointer, 36" lathe, floor model Drill Press, 12" disc/48" belt sander, Dust Collector, work benches, small tools and over 1400 bd/ft.(stored vertically) of wood and it is more than big enough for my needs. Always keep all of your tools mobile, no matter how large your shop is.
Spend more than enough time planning, don't rush it and it will serve you well.
Good luck,