Odd -- did UltGar come back & delete his post or something? I went down to Home Depot & picked out the T-8 fixtures based on his recommendation. Got two 8' fixtures that each take four 4' bulbs. The T-8 style have a smaller, lighter ballast; the bulbs are skinnier, they light up instantly - like incandescent - and best of all NO HUMMING! :xyxthumbs
Had wanted to say thanks to Steve (ultgar) for the information, hope he's still around.
The builder had put a single bare incandescent in the center of the ceiling (gotta love 'em). I'd originally replaced that with a single 4' fluorescent fixtue, 'till I started coming here

. These two 8' units I placed in line w. the cars, but only 28" from the outer walls. When I'm swapping brake pads, etc, on the outer wheels it used to be pretty dark over there. Now I'm thinking about putting another pair of 8 footers across the garage, near the doors. More light when I'm working on the motors.
Used that blue flex conduit to run the Romex to the new fixtures, it came out looking pretty good! The challenge was attaching each end of an 8' fixture to the ceiling w/o a helper to hold up one end while I got the first end started.