There’s some ‘warm white’ GU10 LEDs from simplyled.co.UK for £12 each. A guy at work bought about 20 for his kitchen and lent me one to try. The light output is identical to a 50w halogen in colour and brightness. They’re the ones with 20 LEDs (2020 SMD?) and are rated at 300 lumen/4w. I’ve just ordered some 30 LED ones from Deal Extreme for £4-5ish, if they’re rubbish they’ll go on eBay and I’ll get the £12 UK ones.
A different guy from work built a huge extension that has 60+ GU10 down lighters in it, he’s had loads of problems with CFL ones failing, he’s looking at swapping to LEDs.