Best bang for the buck, IMO, is still a 4' flourescent, electronic ballast, twin T8 tubes. LED will probably pass it in a few years, but the cost right now is just too high, unless you basically build your own fixtures from parts (a project I plan to do for my new warehouse/garage, which will have no electrical service but will have a small solar panel, deep-cycle storage battery and hpme-brew 12V LED lighting). T8/electronic ballast still has a slight warm-up time, but it starts at higher luminance than the old magnetic ballast and T12s, and 10x the initial brightness of a lot of CFL cr*p bulbs on the market. Its pretty good in lumens/watt, too, though both T5 and LED win that. T5 is great, but its too late on the scene- LED is going to drop in price faster than T5 will be able to match and it'll still have the life and warm-up problems of all fluorescent variants.
CFL is absolutely a dead technology. I wouldn't waste another penny on a technology that is literally the worst option currently available. If you've already got a lot of fixtures with conventional Edison-base sockets you want to upgrade, look at the Cree LED lineup. You can get the plastic-case "4-flow" model for around $5 at Home Depot. the better glass-shell Cree is still around $9 for a 60-watt equivalent. Far, far better performance (no warm-up, much longer life, more lumens/watt) than CFL.