Mm... if I had a 120 gallon tank?
For starters, I'm a fan of lots of flow. The bigger the pump, the better. I also do not like sand in my tanks... so my setup will not work for a tank with a sand substrate without some tweaking. With that said, this will limit what you can keep. Basically all substrate living fish/inverts wouldn't be suggested. However, most other fish will do just fine.
Anyways, for the general look, I would put starboard on the bottom of the tank, and stack 120+lbs of LR, or LR+base rock depending on budget. As for aquascaping, I would try to minimize the amount of LR that is actually touching the starboard. This would make it easier for your water flow to remove detrius matter from underneath your rocks. I would probably light the tank with 2x250watt 10000k MH bulbs supplemented with 2x110watt superactinic VHO bulbs. That said, the tank would be a mix reef, with the more light demanding corals on the top half of the tank, and the less light demanding corals on the bottom half of the tank. Fish would include at least a pair of clowns (any species), and an algae blenny.
For return, I'd go for something with enough flow to give your tank a decent turnover rate through your sump. A Mag18 ($184.95 over at
www.jlaquatics.com ), or a similar pump (depending on your budget and whether you want the pump to be internal or external) would suffice. I'd plumb the return to give your tank some nice surface aggitation. Afterwhich, I would buy myself another pump for a closed loop. Something like a Sequence Reeflow Dart ($384.99 at
www.aquaria.ca ) will give your tank a lot of flow. I'd plumb that into a Ocean Motions four-way valve ($399.99 at
www.aquaria.ca ) set with a "1+3" and "2+4" revolving pattern with a 2 inch inlet and 1 inch outlets. From the four-way, I would plumb outlets "1" and "3" to one side of the tank at the corners, and outlets "2" and "4" at the opposite sides as close to the bottom of the tank as possible and have "1" blow against "2" and "3" blow against "4". The four-way valve should give the tank some nice oscilating flow patterns, and it will keep detrius matter off the starboard. I would probably add a flare or round nozzle to the outputs as well, to give me better control as to where the water is directed. As an alternative, I would probably plumb the four-way valve into 3/4" 360degree Ocean Motions Revolutions ($39.99 at
www.aquaria.ca ) and have each Revolution plumbed into a corner of the tank. Of course, all pumps will have a ball valve attached to its output, to give me the ability to slow down a pump if I want to, and all stretches of plumbing will have at least one union in it.
Water topoff would run through a RO/DI unit, controlled by a pair of top-off switches and a solenoid. The water would run through a kalkreactor, before hitting the tank. If needed, I would also run a calcium reactor on the tank as well. Skimming would be provided by as large of a skimmer as I could get. Probably a medium sized Euroreef.
If you can't tell, I've been thinking about a future tank for awhile now... since I can't setup anything bigger than what I have now, it gives me lots of time to plan
If you want to save money, try DIYing some of your equipment (ie. the calcium and kalk reactor, and the skimmer). There are quite a few people in Calgary who have DIYed some of their own equipment, and I'm sure they'll probably be happy to give you a hand.
Good luck with your setup! Keep us posted on it.
-Richer