You should read through the thread on my shop build as Bill suggested. Tons of good ideas there from lots of folks that have been through the process.
My shop size and location were dictated by county and HOA rules and regulations. The building ended up at ~24' x 26' outside. We decided to go with a 1.5 story to gain the extra space upstairs. Access to the second floor is by stairs on the outside rear of the building so as not to use up the floor space in the shop.
Ceiling height in the shop is 9' which seems ok so far. 10' may have been nice, but every foot adds a little more to the costs, and to the number of steps to get to the second floor.
My lights are plug ins hanging on short chains. I've already bumped them once or twice, so they will be raised up a little higher. The plan (eventually) is to run 6" pipe for the DC along the ceiling. Still have work out where to run the pipe and how to work it around the lighting.
We also had the building built on a crawl space instead of a concrete slab. My legs and feet thank me for that decision every day. I put in a few hours out in the garage on the concrete floors this past weekend and my legs were aching by the end of the day. I can easily work 8 hours straight on the wood floors with no problem.
Put in a good sized panel for your electric. A 200 amp panel only costs a few dollars more than 100 amp panel. Add lots of outlets evenly spaced around the room. I also had two 20 amp, four gang, 120 volt circuits and one 30 amp 240 volt circuit run to the center of the floor for the tablesaw and router table, etc.
After working in my garage last summer and winter, HVAC became a top priority. With that, insulation became a must. If you can't do both right away, I would insulate now and add HVAC later, if and when you feel you need it.
