I would go with sand. If you plan on getting a protein skimmer, which I recommend, no external filter is needed. I actually have both. I have two bio-wheel 280 filters and a 105g skimmer on my 90 gallon. Koralia makes really good power heads. Try to move 30-50% of tank volume. I'm moving 2850 gph
in my tank. Also, do plenty of research on lights. Get lights that will work best for the tank you want and the corals you want to keep. Anemones need really strong lighting so go big if you plan on getting one in the future.