I can't say I care for the color of the light. It looks really blue in the picture, but maybe it looks different in person.
But with that much light, you'd really better get moving on the CO2. I only have 216 Watts over my 120, and it had algae problems before I bumped up the CO2 a few months back. As for recommendations, I believe that Rex Grigg sells pretty much everything you need for CO2. I bought my stuff from Foster and Smith, but I don't think I have the best regulator in the world.
Good luck. 120s are one of my favorite tank sizes, and I'm sure it will work out well.