if i were getting it all over again, i would
get the overflows drilled in, instead of a hang on, i would get a summp set up in the stand, before i put the tank on(believe me, it is much easier)
other wise, are you going with a reef, or a fish only?? equipment would be similar, but a fish only is less strict on what you need for lighting and filtration, and such, or aggressive fihs should have more aggressive filtration
but you will need lights(your goals will help alot here for requirements), substrate, i prefer a dsb(deep sand bed of 4 ot 6 inches), circulation and filtration, i like a dsb and lr with a skimmer(the lr and dsb serve as natural filters), and some powerheads for circualtion
OH, AND VERY IMPORTANT, A GOOD saltwater TEST KIT, you want to monitor phosphates, ammonia nitrates, nitrites, ph, alkalinity nd calcium(especially if you are going reef)
and a god book to read is IMO, the new marine aquarium by michael paletta, it is very easy to understand and answers alot of questions and walks you through the set up , step by step adn explains everything very well, and helps with the selection too