I've changed all of my halogen downlights for LED's. They do not last for ever though. I've had one fail after a year or so. But they do not fail as often as halogen ones and I have probably saved through not having to replace them as frequently. The light quality is good and I find cool white or white light is better than warm white. They are of course cool compared to the halogen which are very hot. The remainder of our lights are all energy saving but not LED.
Farming Today, early this morning, on BBC R4, was all about renewable energy.
A corn-on-the-cob (when suitable processed) can power a low-energy [LED] light-bulb for up to 6 hours!
click here I use 4 LED lamplight's in various locations in my house ... for bedtime reading and at my computer[s] ... saving money ... in-the-long-run, hopefully. [I incorporate 'plug-in' mechanical and electronic timers, as well, so they switch off when not required].
Have no CFL's. Will slowly change to LED's in kitchen (16 downlights) when current ones fail. Lighting is a very small part of my energy bill, and so far I have not seen LED's that are as good as incandescent or halogen ones. The ones I have seen seem to have a bluish light.