I'm also a newbie at this stuff and for the past few weeks i've been to different pet stores, talked to numerous people on this forum and been on about a hundred internet sites figuring out the same question fw or sw. Basically, in a nut shell everyone already said it... for someone new bigger is definitley better if you go salt, everything is easier... water control, pH, nitrates, also the types of livestock and of course how many also improve, and compatibility of livestock is lessened in a bigger tank. From what i hear anything under 55gal is a huge can of worms when you do salt... if you aren't already experienced. Also a tidbit of info that i was given was that no matter what type of tank if salt... Fish only, with live rock or a reef, you should by reef equiptment - it will work for any type and if you want to upgrade to a reef you don't have to upgrade your equiptment. Good luck and remember take everything in as a grain of salt... get many opinions before you do anything and also make sure it is what YOU want.