i converted my friends 10k sq ft shop w/ 18 ft ceilings, from metal halide to 4ft, 6 bulb T8 fixtures 2 yrs ago. the power company had rebates and calculated the energy savings payback to 2.5 yrs. very efficient lighting. we do have a string of the 8 ft HO fixtures, 110 watts for each bulb and they do not last long. i have not replaced any of the T8 bulbs, but have had to replace the HO bulbs 2x in 2 yrs. it seems that they have max output for 6 mth or less and progressively go down to black ends.
my own shop has a grid of switched outlets on the ceiling. i use a mid-range/cost 4ft, 2 bulb T8 fixtures with a wire cover as my shop ceilings are @ 8 ft. the cheaper fixtures do not last and have hard start times in the coldest part of my shop.
for work lights i have a couple of 300 watt flood lights that i can move around on the floor or hang from strategically placed hangers on the ceiling. and a fluorescent work light.