Here's a diagram of what I just finished installing a couple of weeks ago(not pictured, 6 more lights on a 3rd circuit in the "upstairs" storage area.)
I mounted switched outlets in the ceiling and hung my shop lights from nearby hooks. That way I can easily replace an entire unit if need be. I wanted units with T8 ballasts but with this number of lights the price was too much. I settled for T12's running 4100K 40W bulbs(a hair closer to daylight than 3500K. If I had my choice, I would have liked something in the 5000-5500 range).
One thing that made this compromise a little easier to swallow- I found shop lights made of chrome diamond plate
! Very appropriate for the garage environment in my opinion, and not nearly as pricey as the T8's.