Plus, let add a little to some of the other stuff that was said: (1) everyone keeps mentioning that a sump adds water volume, but they haven't said why that's a good thing; quite simply, the more water volume in your system, the less likely any one problem is going to affect the tank/raise any of your levels to a harmful level abruptly. All our parameters are about dissolved content percentages (i.e. how much ammonia you have per water molecule, etc); so, while having a larger tank is more expensive and gives you a crap load more stuff to look after, keeping the water parameters in check is actually easier. (2) Not only should you stick to rectangular tank, but you should also try for one that is 48" long if you plan to upgrade later as you will most likely be able to keep your light, and if you see the prices of lights, you'll understand why you may want to try and re-use your light down the road. (3) Remember, there are two kinds of live rock, cured and not; for cycling your tank try to get at least that pound per gallon of non-cured, cool looking rock with crevices or odd shapes that you can make caves out of; then, when your tank cycles, get a decent chunk of cured live rock (say somewhere around 10 pounds) with a bunch of coraline and hitch-hikers that will then transfer to your other rock. Just make sure you leave room to add that extra rock. Then wait a few days to see if your tank starts to do a little mini-cycle. Once that's all good, go for the fish.
