I like the theory of CFL bulbs a lot. As far back as 1992 in my grad-school apartment, I tried to go CFL because I found out the local utility had a program of selling them at huge discounts (which back then meant they still cost a little more than full retail does today). Back then, that got me two 16W bulbs twice the size of a 23W spiral of today, that took 5-10 min to warm up, a bit of hum, and that always looked "muddy". My roommate insisted we go back to incandescent.

The CFL case is much better today, but still not 100% there.

Tom is right about the lifetime issue. I even find that lifetime is reduced if they are installed base-up vs base-down, presumably because of the hot air rising into the electronics. Still good vs incandescent but not always the 10,000 hours advertised.

There there is temperature. While much better than those 1992 models that needed long warmups at 68 degrees, what about applications that are not "room temperature": garage lights, porch lights, other outdoor lighting, even lighting in basements, utility rooms, or what we in New England call "mud rooms" (a large entry room for taking off one's snowy/muddy outerwear, often an enclosed former porch or other poorly heated space). My laundry room, for example, hovers around 40 degrees during the winter with the house set at 68. The porch and the garage are ambient.

Even at 40 degrees a CFL sucks. At 20 degrees you need to plan your moves and turn them on well in advance of needing the light. Note that if this means leaving the laundry room light on all afternoon vs flipping a 75W incandescent on for a couple of minutes at a time, total energy use is _higher_. At -10 a CFL may not even start. WHat happens in New England or North Dakota when we ban incandescents?

Then there is light quality.

CFL is not blackbody. It's just not. As someone long into both photography and astronomy maybe I notice light more than most, but I really notice the spectra of light sources.

Even regular incandescents annoy me since they are so warm vs solar. For applications I care about I use halogens or at least coated bulbs like the GE "Reveal" series. I'd love for my whole house to be light by museum-style cool-white, well-focussed halogen floods, but that's just not feasible for lots of reasons.

CFL is better than it used to be but still not there. Most of the regular bulbs (2700K) are too warm, and usually have odd greenish or sometimes purplish notes relative to a pure 2700K spectrum. The 3500K bulbs are better, usually, but tend to be missing some red (and are more likely to flicker and hard to find in high wattages). The "daylight" bulbs are way, way too blue, like a TV set on static (which might actually be closer to daylight but the way the human eye works, doesn't look that way at that level of intensity).

I'm fine with CFL as base lighting, or in places I don't care about much. But I have some nice halogen desk lamps, halogen torches in the living and dining rooms for extra and/or better light, and the kitchen is all halogen floodlights. Mostly it's the color, but also focus -- you can't make a good flood/spot with such an extended light source. If I'm going detail work like reading or food prep, I want a very crisp point and focussed point source.

If they move to make incandescents illegal nationally, I'll be stocking up like NRA members are doing with ammo....