well I have lived and breathed saltwater for the last few weeks reading everything available!
Get a pre-drilled tank, the largest rubber maid tub that will fit under your tank in your stand, and an appropriatedly rated pump, now you will have to decide to do a reef or a fish only tank. If you want to do a Fish only, you will need to set the Sump(rubbermaid container) up as a wet/dry filter. If you are going to do a REEF, you will need to set it up as a refugium. In addition, For REEF, you will need a VHO lighting system, for Fish only you will need just regular flourescent lighting, Cost is about a $200 difference. Also I recommend going with an all glass hood, not those plastic pieces of crap. Also you will need 3 good powerheads with pre-filters. Saltwater is a completely different game than fresh water! At least that is what I am finding out! Don't forget the heaters!