In reply to Climbing Pieman:
Before we had our kitchen re-fitted, I changed all the screw in spots we had to LED GU10 using inexpensive screw in adapters we got from Am£&*n. Worked well. Personally I'd give halogens a massive swerve: they are generally too hot (meaning that their surroundings blacken after a while) and they seem to be incredibly unreliable.
As far as I can tell, most GU10 LEDs are about the right colour for the kitchen - you have to look a lot harder for properly 'warm'