CFL's good or bad?

Yea, there is a very small amount of mercury in a CFL. However, there is a great deal of mercury in coal, so you actually put less mercury into the environment by changing from incandescent to CFL. You do need to take a few precautions with a CFL light if it breaks, and it should be recycled properly when it finally burns out.

LEDs are getting better very quickly, but as of today, CFL is generally your better choice. CFL is still much cheaper to make, gives better color, and it's energy efficiency is about the same as the newest LEDs.

However, wait about 2 years, and I think LEDs may take the lead.

Your best source of information about LED vs CFL is probably CandlePowerForums.

I've been using CFL's since 1990 when I saw them in Home Depot. CFL's are completely inappropriate to use on a vehicle since they're so fragile, so you must be meaning home use ...

There is some concern about mercury .. but as noted the lower electricity requirement means less coal burned and less stuff including mercury released due to burning the coal. That makes it a net win.

There is another issue with the mercury however. The rising demand for mercury (for CFL's) means more mercury mining is being done. Increasingly the mercury mining is being done in China. China does not have anything approaching the efficiency of OSHA and there are lots of reports about horrid working conditions for mercury miners in China. The short story is the environmental concerns driving people to use CFL's is causing an environmental and health disaster to supply the products. See: 'Green' lightbulbs poison workers

I like the idea of LED's but haven't been able to get past sticker shock. I do use them on my bicycles though.