I went down to walmart late last night in frustration because the power saving bulbs I had in my main light with a dimmer weren’t working. So I switched them (two bulbs) to GE Reveal 71367′s (not an affiliate link), the most expensive bulb I could find at $4.50 each and one of the few to claim to work at different voltages. I’m in love with these things, mainly because they work perfectly with the dimmer in my office and they change color from a cooler (more yellow/orange) color temp to warmer (more white) as you crank up the voltage. The highest setting has a very natural looking light, closer to daylight which keeps me from dozing at my keyboard.
Let me know if you’ve found something better!