I like the sheetmetal reflectors. Generally they reflect the light downward at the expense of indirect light which will bounce off the ceiling and the high portions of the walls. If the ceiling is painted white then the reflectors might not be needed -- the white ceiling acts as a reflector and you might save a few bucks with "strip" lights that don't come with reflectors. Still a good portion of the light will end up high on the walls instead of on the work area.
Also its possible to take some sheet metal shears and cut the refectors at the ends a bit so the reflector can be bent upward exposing more light to the sides of the fixture. I did this a while back for some indirect ligting (not in this garage) and it worked just fine. You can always hack a little to get things just right.
Also for fixtures check out Lowes -- I think they have a couple brands not carried at Home Depot. And last year I noticed that the TrueValue Hardware web page had fixtures on sale and available at the local indepenent hardware stores.
Forgot to mention that the "lumens" rating is the actual light output of the lamp (when new). The higher the lumens and lower the wattage the better. Harder to figure is the efficiency of the ballast as this is often not in the manufacturer's specs.
One last thought: you need to figure the operating cost difference between lamps and fixtures compared to the original purchase price. If you have to spend an extra $100 to save a penny an hour in watts, it will take some 10,000 hours of wrenching in the garage to break even. In my case I'll be dead before that happens.
