I quite like my IceCap 10K's that I got from
http://www.aquariumlight.com/product_info.asp?dbid=651
I prefer 10K's because I prefer to be able to control the blue light via supplementation rather than have the blue coming from my MH permanently. That way I can have high PAR for the corals when I'm not looking at the tank and then only turn on the supplemental light (for aesthetics) when I'm looking at the tank which isn't going to be as often. Hard to beat the price of the IceCap 10K's as well.