Agree with comments above and will add: I used incandescent and put in cans (or high-hats, as they're called some places). In my 7x7 foot space I used 6. It generated a lot of heat and it was quite bright with 60w bulbs. I find that I unscrew the lamps in half of them much of the time.

I wish I had planned a spot for a swinging, articulated drafting lamp. A task light that you can swing about on the enlarging table or on the shelf over the sink would be useful. Since you're in the pre-build stage, I thought it was worth mentioning.