After some consideration, I have chosen to install a sump for my newly 55g future reef tank. To eliminate the use of powerheads all together I am going to make a manifold using this concept (http://www.advancedaquarist.com/issues/sept2003/short.htm). If anyone has thoughts on this please respond. The big concern I have is the construction of the actual sump. I have little knowledge of how to build one from scratch but if given a blueprint of an ideal sump (maybe refugium in there as well) that will fit in a boxed area of 29x15x21", I could build one with the right materials. Also for the overflow box, could that be manifested from materials as well or would I be better off buying a premade one from Marinedepot or some other place online. External pump to push water back to tank, recommendations at a reasonable price? Whoever is up for help and information, expect me to have a few more questions =D
I couldn't have made mine without these pages!! Spend a few days there and you'll definitely get some good ideas.
I used a simple leftover aquarium as the sump and had glass cut to fit my design. Knowing the footprint of your skimmer before you make your final decisions is a real good idea!
As far as overflow boxes- if you have not yet set up this system I would truly suggest you have the tank drilled. Boxes are expensive and prone to flooding. Many workarounds (discussed on the above referenced site) but drilling is far simpler.
Choosing a pump would to a large extent depend on the amount of water your overflow can handle, and the above manifold system will need consideration as well. I would wait on the pump choice until I have all these other things determined, but a Mag 9.5 would be my ballpark choice.