Built in tanks are very nice my cousin had one in her TV room that was also seen in the family room. I'm not sure I would choose the dinning room as you only are in there for 20 or so min at a time where if it is in the family room you would have more viewing pleasure JMO I love watching fish tanks if I didn't go away so much I would have one.

I helped DS install one a couple of years ago. It's a 65 gal (high) and is 24-30" high. I can't remember actual height but I know it's too high to easily service. One has to remove the lights and then get a ladder to do more than feed the fish without using an extended rod of some sort.

Do you have the extra room to keep the equipment necessary to run it? Do you plan on having a sump tank?
Will you be taking care of it or a hired service? I ask because that will play a part in just how large an aquarium you should get and where it should be placed.

I will probably inherit DS's aquarium, but I don't want all the bells and whistles that it now requires. Instead, I'll take all the fish, etc. and will be buying a NanoCube by JBJ to house them in. Excellent lighting, no heat build up, and everything is built-in. I've seen a unit in a friend's home and it looks great!
Check the link below for the one with LED lights. I've seen better prices........

Here is a link that might be useful: Aquarium

We would get a service to handle it. If Salt water they would come 2 or 3 times a month once it was esablished, maybe weekly to get it going intially. If we did the built in, I figured the cabinetry at the bootom and using the space at the top would house the necessary equipment - filters, pumps, etc. If we bought a freestanding, the equipment usually comes hidden in the cabinetry.