I think the lack of response is due to the question being simply too broad.
A good week reading as many post in the Large tank forum as possible will give you a good start. Find out what people used, and find older tanks and see what they changed or regret.
My 2c anyways.....
Glasscages, Marineland, and Miracles are good if you go glass over 180. Otherwise you can get a 180 from most any Mfg. but I'd still go with these three if I didn't go custom.
Closed loops allow you to hide stuff, but are ALOT of work. If you are not in for a major project - then stick with powerheads, waveboxes and fake tunze rocks. To have a closed loop work flawlessly requires planning. Powerheads on the other hand, can be moved.
That said I love my closed loop so far.