There are a couple ways you can go. Since I am planning a 40 breeder and have been for months, I have thought for MANY, Many hours on how to light a 40 Breeder. Here are some options:
1) ATI Sunpower in either of the following sizes; 4x24W, 6x24W, 4x39W, 6x39W. An issue I see with the 6x39W is too much light. You will not be able to keep LPS all that happy. SPS will grow anywhere you want however.
2) Run a TEK 6x39W. I don't care for TEK fixtures as they have no fans and the reflectors are some of the worst on the "higher end" fixtures. If you go this route make sure to get a fan to cool the fixture.
3) Get a Current USA fixture. Cheap fixture but you also get cheap ballasts and cheap reflectors or should I say reflector. Most of Current's stuff does not have individual reflectors. On a shallow tank it doesn't make a huge difference to have individual reflectors though. Just know that if you go this route you will want to replace all of the 10K bulbs at the beginning. So factor that into the price.
4) Go with the cheap ebay crap and just spend more money later getting one of the three I mentioned above. LOL
I personally am going with the 6x24W ATI Sunpower. I will be able to keep LPS on the outskirts of the light and keep SPS and clams underneath the bulbs. I will also be running at least 1 if not 2 Actinic bulbs to help lower the overall PAR.
Hope that helps. You can call me also if that helps!