[pogodzib]

In general, the largest tank you can afford to keep, the better, due to a larger volume of water making the tank more stable. However, you also need to be able to afford to fill the tank with corals, fish, critters, etc... and all of the equipment to go along with it.

As for the skimmer, I prefer high quality stand alone skimmers over any all-in-one/optional/boxed type of skimmer. Next to lighting, protein skimmers are the single most important piece of equipment. Usually optional type of skimmers are way overpriced. There selling point is that they are made for the tank and how they look, not how well they function.