Human beings evolved to see best in sunlight. Direct sun is about
10,000 foot candles. Open shade, blue sky, is about 500 foot candles.
It may be too much cost or too much heat load to light your entire
shop to that level. But don't go below about 250 foot candles if you
want to enjoy working in there. Shoot for 500 to 1,000 foot candles
in the places where you really have to see.

You must own some stock in sunglasses. I have been working on a
relamping project at work. One of our test areas has ambient lighting
at 150 ft cnd (at working height) and it is exceedingly bright. Most
of the areas are at 60-80. 100 is our optimal goal. You are never
going to get enough light even enough to avoid task lighting. Loosely
quoted standards are as follows:

General lighting 60-70
Detail work 90-100
Assy work 70-80(maybe 90)

Depending on your ceiling height you have a few options in current
lighting technology. Less than 12' and you are restricted to
flourescent only. If so, go with T8 style fixtures. They are very
nice. If you are 14'+ you can start looking at Metal Halide fixtures.
They have a better color rendition, but they have a bit of a slow
start drawback(with pulse start, it's about a minute cold). They take
a lot longer when they are hot.

JW