sure, the minimum flow needed to prevent surface scum, as well as enough to feed any skimmer/refugium you might have. Sometimes you might need to have a certain throughput on a skimmer otherwise you might be limiting its performance. This amount may not be that high. The deltec on DNA's setup has a throughput of only 100gph...and the pumps do somewhere between 600-1200gph of recirculation style skimming. A refugium might need more flow, as caulerpas and macros do better with more flow...however a recirculating pump or powerhead might be all the flow one needs to keep the macros happy while the actual throughput stays at only a few hundred gph.
As for my tanks, I make them with either the sump built into the tank (using a fake wall+overflow to section off part of the tank and stick everything in there), or with the sump in a cabinet next to the tank, so minimal head pressure is on the sump's pump. If I have the in tank sump, a good efficient pump like an eheim goes in there for flow...as head pressure isnt a real issue. If the tank does have a sump, its flow through is minimal. I make the tank circulate with low-wattage, low-head, high flow pumps and powerheads on closed loops. No sumps with 4+ feet of head pressure, no basement sumps (maybe the room next door or in the closet, but not on another floor).
As for lighting, the best bang for the buck is halide. Although T5 has been used with good results and does have its appeal and applications, myself and others have experimented with the two types side by side and noticed that corals just seem to like halide's complete spectrum better. To minimize heat, and the need for cooling with a chiller, open top canopies are key. Hanging a halide pendant over an open body of water allows for better ventilation and cooling of the light bulb than most any other setup. Rather than a cover, if you have jumping critters, use a 'collar' to go around the parimeter of the tank so that any jumpers will be left to jump, or bump up on a side wall. Making the most of your lighting is key. The most effective use of a halide is with a wide, deep, and shallow tank. A single 250wattDE bulb can be used over a 3'x3' area as long as the pendant is hung high enough and the water is kept about 14". This might not appeal to everyone, but I tend to like the 'lowboy' look. Theres nothing cooler than being able to look down on those dazzling ultra clams that you otherwise wouldnt be able to with say...a 180g. Thats about it. Just use the electricity wisely. Lights, circulation, oh, and heating. Some tanks dont need much help in this category, but if you live in cooler climates where your room temps might go low when the lights are off, and you heater actually gets use, you might want to consider one of those low-voltage heaters that sits under the tank. A small 50watt model can heat about 100gallons because of its excellent radiant coverage.