Another vote for the T-5 High bays with 4 bulbs. I have 4 in my 30x40, all in one line across the 40' span. They light it up like you can't imagine. They are plenty. I've only ever needed more light when I'm way up in the underbelly or deep into the engine bay.
Another thing for shops: Heated floors. Before putting in concrete, invest in the pex and run it throughout your floor. Mine does NOT have that, and I a buddies does. I went to his shop when it was freezing, and it was great. His costs for keeping it heated are so much lower than mine, and mine is better insulated. I can deal with hot as balls as long as I have a fan blowing, but when it's so damn cold you can't move your hands, screw that.