Sorry you can't swing the shop now, but I'll throw in my pole barn experience after owning three just for future reference.
My current 30 x 50 12ft ceiling pole barn cost $40k to to have built by a contractor including the materials kit and trusses from Sutherlands, grading the ground, cement floor and 30 x 25 outside cement pad/sidewalk, 200amp service/electrical work plus drops for lathe and compressor, lots of insulation, two 10 x 10 garage doors, propane fired radiant heater, interior walls/ceiling finished with OSB, and fiber optic cable run from house to shop (for work purposes). The contractor was recommended by Surtherlands, he was an odd dude, but his crew did great work. The shop is solid and not a lick of issues in 11 years. It always stays about 15deg cooler than outside during the summer, and never gets below 40 in the winter if I leave the thermostat off over the weekend.
$40k isn't cheap. It's downright painful, but 11 years on it was money well spent (or borrowed!).
Insulation and heating has always been the main issue with the shops I've owned. I've used wood burners, built double barrel wood/oil burners, fuel oil fired forced air heaters - all suck for one reason or another. The overhead radiant heater is the best system I've used, it heats up the floor and everything in the shop so that when you open the big door to pull in your truck/whatever it's still warm right after the door gets closed.
Electrical service is another thing not to skimp out on. Blowing the main mid-weld because the furnace was running and the compressor kicked on really sucks, you end up tripping over crap trying to get to the breaker box in the dark!
And...no matter how much you are in a hurry, paint the walls and ceiling before you start moving stuff in.