Hi, A couple of things to keep in mind would be whether you can reach the bottom of the aquarium to arrange things and clean it and the surface area of the water for oxygen exchange. I do think that a taller aquarium makes it nicer to view the fish though. Weight is an issue but only a couple hundred pounds at the most. You need to plan where you place the aquarium regardless of size. Another factor is availability, what do the dealers have in stock as far as stands and lighting and how they priced for the complete setup. It is usually cheaper in the long run to buy everything you need at the same time and try to get a good deal on the package. Have fun.

While I agree that a tall tank can make for nice viewing, especially when growing particularly tall plants, I also concur about oxygen exchange and why, as interesting as tall tanks can be, I would never have one for live fish.

The greater the surface area in relation to gallons of water the better and in any case, the deeper the tank, the greater the light intensity needed to grow any plants, as the light must penetrate through that much more water and the deeper the tank, the more powerful an air pump is needed too.

As generator also wrote, there is availability to consider. To wit: 55's are the most common size in slightly larger tanks, so both the set-ups and assessories to fit them are also the most available and thereby, least costly. The wider width in proportion to volume of water also places less stress on floor joists.

A standard 75 gallon tank which is the same length as a 55 but wider front to back would be perfect. Decorations can be easily fit so that the aquarium has the look of a lake or river bottom more easily in the 75 because of the greater width front to back. Deep tanks are better looking but as soon as you reach in to your armpit to clean the lower reaches of the aquarium the allure goes away.

paparoseman:

A standard 75 yes, regardless of soaked arms, but the OP referenced a 75 Tall. Perhaps I took them too literally, but when trying to correctly inturpret the written as opposed to spoken word; one has no other option.