Welcome from a fellow FNG!
I'm in a similar, albeit slightly farther ahead stage . . . have a AGA90g w/overflow sitting in the wife's office. Already picked up a MegaFlow 3 sump, and have filter pump, powerheads, heaters, lights and a few odds-and-ends on the way.
I've discovered there's three secrets to a successful salt water tank . . . research, research, and research. And when you think you've researched enough, research some more! Actually a never-ended part of the hobby and I imagine even the "Old Salts" will state that they're constantly learning. We're approching the three-month point since deciding to have a tank, and everyday we're pouring over our books (The Conscientious Marine Aquarist-Jenner, PocketExpert Guide to Marine Fishes-Michael, and The Simple Guide to Marine Aquariums-Kurtz) and cruising the various websites. Be aware that you'll come across many conflicting statements and opinions, although sites such as this, utilizing direct experience, is probably one of the best resources.
One of the larger aspects of research is picking your livestock. Our prospective fish-list has changed innumerable times, and probably will some more before we got to the acquisition stage. Compatability between specimens, eventual growth, feeding habits, bio-load are all things, among others, that have to be considered.
There is one inescapable fact . . . this endeavor will cost money, just no way around that. There are many things to mitigate cost, such as prudent shopping, DIY if you possess the necessary skills/capabilities and careful planning to avoid problems, but consider that since you'll be investing a lot of money, don't jeopardize the whole project by trying to lowball certain elements. Our philosophy is to go for quality, even if it means thinning the wallet. Don't want to put a couple of thousand dollars into this and then have the tank crash because we went on-the-cheap for some minor piece that ended up being crucial. We're even going so far as to have the non-grounded electrical outlet by the tank replaced (At a fairly substantial cost) with a GFI unit, as well as an additional GFI outlet running on a seperate circuit on the next wallstud to avoid cord-kluge and mitigate electrical issues.
Last bit of advice . . . patience. You're looking at probably two-three months at least before you'll be gazing at your fully operational aquatic wonder in its early stages of stocking. Savor and enjoy the planning/building process, I've found it's actually an enjoyable aspect of the hobby and hope/anticipate that our careful planning and slow-moving efforts will yield a highly satisfactory experience for years and years.
