I bought super bright wide angle LEDs from BikeHighway (I think mine were 1150s) and am very happy with the result. I got the wide angle ones as some people had mentioned concerns over the focused direction of LEDs (ie. straight back). The wide angle ones have some bulbs pointed off to the side so that you get a better spread of light.
Ideally I would love to have modulated brake lights as I really notice them on other bikes.