Welcome to R2R! There are so many good tanks out today that it would be hard to make a recommendation. Most of them are pretty good. If you want a tank that has all the essentials with it, Red Sea is worth looking at. If you want an almost there tank, Innovative Marine or Waterbox are good. That said, there are literally hundreds of good tanks out there today. Almost everyone makes a nano (the tank sizes you mentioned are typically considered nano tanks) of one sort or another. Fluvals are very popular as well. Visiting a few local aquarium shops and looking at the tanks they offer should help you decide on a style and maybe even a brand. Good luck and ask questions on R2R! The people here are always willing to help.
