I agree with what Kipass stated about the radiums. When overdriven, they do have more intensity, but it can be expensive replacing them every 6 months. When they're not driven on an HQI ballast, they will last longer, although they won't be anywhere as intense as other halides.
The 250wt 20,000k Radium has a much lower PAR than other halide bulbs.
I would recommend the 10,000k Ushio. I've used it for a few months without any supplimental actinics, and I've really enjoyed the coloration and growth I've gotten from my corals.
Graham