I've got 240 volt downlights and I've replaced almost all the halogens that came with them, with 11watt CFLs. They take a little while to get bright but they put out plenty of light. I've also replaced my 150Watt portaflood with a CFL. That one is very slow to brighten up (at least five minutes), but it's really bright when it gets going at full steam.
I've also replaced two of the downlight globes with 0.5 watt LEDs @ $16 each. The light output isn't quite as good as the CFLs so I'll wait until they get better and cheaper, but they're supposed to last up to 50,000 hours so that's even longer than a CFL.

The guy at the lighting shop showed me a new 240 volt LED downlight globe with a single light instead of the usual multiple globe arrangement. It was 5 watts, but I'd say that it had a similar output to my old incandescent floodlight of 150 watts. It was incredibly bright, but unfortunatelly it cost $60. He had a three watt version that was about the equivalent of an old 100 watt globe, but that was $50. I'm sure they'll come down in price though.