About 1/5th of my lights in my house are compact flourescent bulbs.
[*]I use them in my computer room because they are brighter (the room is in the basement and needs it) and since I use that light so often.
[*]I use them in my storage room to have light on 24 hours a day. My cat's food/litter are in there and there is no light from any window, so even a cat couldn't find them in the dark. I didn't want a normal bulb on 24 hours a day in a room I don't use.
[*]I use special daylight colored CFLs in my walk-in closet. I like the color produced by those bulbs more than any other bulb. I can differentiate clothing colors so much better in there than the dim normal bulbs I used to have. For example, I used to have to guess if an item was a dark midnight blue or if it was black. With the daylight colored CFL, I know instantly.
The cost savings of CFL is less than people might think. For one, decent quality CFLs still cost far more up front than normal bulbs. Also, remember that energy produced by normal bulbs heats your house in the winter so you don't need to run your furnace as much. Any savings by a CFL using less energy for me is just offset by needing to spend that much more to heat the house. That latter point depends of course on what climate you live in. CFLs make a lot more savings in the south than they would in the north.
I still wish they came on instantly. The half second delay always bothers me. Plus, when I show people how wonderful they are, they often judge based upon the dimmer warm-up minute and hate the bulbs. I've tried the mixture of normal/CFL as mentioned above to get the instant light + benefits of CFL. However, the result was an odd yellow on one half of the room and a wonderful white color on the other half.
That said, True high intensity LEDs are the light bulb of the future. They will be far superior to CFL bulbs.