I'm running XM 10K with 2 55w PC Actinics and I like the color combo, between the high par value for a m58 ballast and the actinics I have good growth and color.
Go to Sanjay's website for color and rating information on each bulb for your ballast. High par is good for coral growth. According to Sanjay he believes anything above 90 par is good to keep most sps corals. The color spectrum of each bulb will also help give an idea about color in your tank.
Before I upgraded to 400K - and I'm now using radiums - I used the AB 10K 250 with the icecap ballast and I thought it was a combination that can't be beat. I supplemented with VHO actinic and growth was the best I've ever had.