You might want to get some base rock to put on the bottom. It'll become LR
in a few (like 6) months. I got base Reef Rock 50lb (Carib Sea) from www.thatfishpalce.com
for less than $42.00 + $13.00 for shipping.
The rock and DSB
will do most of the filtration so you can remove the filter material from the Emperor and use it just for flow. Does that have a bio-wheel in it? That will probably end up raising nitrates, not a good thing for corals.
You want water flow in the 10-20x/hr range (450-900 gal
/hr in your case). Maxi-jets get good reviews here. You might want to try using 2 Maxi-jet 1200s. I have a couple of Hagen 802's in my 125 and a couple of mini-jet 404 (free in my IO salt buckets) for added flow in the corners.
As Steve said, plan now for what you want your tank to end up as. I keep upgrading and it costs a lot more in the long run...especially lighting.