I've heard/been told that a tank should have a circulation rate of at least 10x the volume of the tank. If you have a full blown reef tank (which I don't), though, I think the circulation should be higher.
Check with Darin at Captive Reefs (another sponsor) as well. I'm embarrassed to admit that I don't have the pumps/powerheads page up on my site yet . You are making a good choice with the Maxi Jet powerheads...they are top quality.
Life is not measured by the number of breaths we take, but by the moments that take our breath away.