My Eclipse 12 was originally a freshwater so if I were to start over again with a nano sw
tank I'd go with the nano cube becuase the lighting is so much better than on the eclipse.
My tank really isn't complex at all. The tank did originally come with a flourecent bulb and it took me a few weeks to search for a compatible 50/50 bulb that would fit the hood. You can purchase them at http://www.hellolights.com/13w5010dayac.html
Then I use the filter and bio wheel that came with the tank. I was originally told to remove the bio wheel and that seemed to work fine, but I later put it back in and still have my nitrates at 0ppm so it doesn't seem to be effecting it in a negative way. :P
Then to add circulation I added one of those powersweep powerheads and I love it.
I have 12lbs of live sand and 15lbs of live rock and everything seems to be running smoothly now.
If I missed anything you wanted to know just ask.