Rates where I live are .2544/kWh, one of the highest in the US.

Years back I swapped all bulbs I could to CFL and converted many to 12v. Now I'm looking into LED. But, like already mentioned, they are expensive. Costco is starting to carry a few now and I pick up a couple boxes each time I go through the store.

Some CFL light immediately. I did not know this at first and ended up buying them twice. Again, go to Costco to get the ones that light immediately. I find they do put out bright, near 4300K light. You just have to look for them.

One concerning point with CFL, is that they are very dangerous if you happen to break one and then step on them. We had a safety bulletin go out at work with pictures. Very gruesome. Be careful changed them, and if they bind on you, don't just grit your teeth and keep turning. Get some gloves and eye protection. And whatever you do, never step on one. You might just have to amputate your foot - no exaggeration.