As for live rock - the stuff is expensive. And since you have plenty of time before you set up your tank you may want to take a look into making your own rock! I got impatient and bought base rock. It only takes about 15 minutes to mix it up and in the mold. 2 days to let it dry. Then a LONG time to "cure". When I say "cure" I'm not talking about drying or the same curing process done for live rock. The pH on the DIY rock is extremely high and you have to leave it in fresh water for several months to leech out the minerals that cause the high pH. I've had some sitting in water for about a month and a half now and the pH has come down a bit, but still entirely too high for my tank.
I plan on making more of it because it's a lot of fun and I plan on getting a bigger tank one day.
The biggest two advantages are cost and you can make the shapes and sizes you want rather than having to make stuff work and/or endlessly searching for a perfect piece. Let me know if you're interested and I'll tell you some more about it.