Realize also that a 6' x 3' x 3' tank will not fit through standard doorways I will be removing a window to get my new tank inside the room it is going in.
Not only that, but the stand is often larger than the tank. Even if the tank was only 2' high the stand would most likely be too big to fit through a standard door (unless you like them low!).
the place we're probably going to settle on actually has a sliding glass door on the porch, and we asked the maintanance guy about a basement, and he said there isn't one.. we decided to hold off for a month until we're moved in.. then we'll do it right and get the 8 foot tank.. it will fit through the sliding door..
8x3x3 but like everyone said "The bigger the better " just don't put too much pressure on yourself in saving money for the 300 because there is still time.