Obviously, without knowing your house, none of us can know where a good spot would be, but one thought I have that is very much an individual choice, but do you really need the larger tank? I know I debated everything from the 65 gallon to a 150 gallon when I was first buying and there were times in the decision process when I was sure I was going to get a 120, then a 90. I'm totally a "bigger is better" guy deep down on aquariums.
I eventually went with the 65 gallon (RSM 250) and ended up being glad I did. The larger tanks would have really dominated my room in an aesthetically less than ideal way and my wife would have been unhappy (although I still wonder if a 90 would be OK from time to time). My living room is pretty large and the 65 gallon is the first thing people notice when they walk in it as is. Bigger might have even started to look a bit gaudy.
I certainly think a 65 gallon in the living room where it's a cool part of everyday life would be better than a 150 gallon in the basement where people spend much less time...and my basement is finished.
Would a 65 gallon have more spaces in your house it could fit? Would you be happy with it or regretting you didn't have the bigger? Those are choices only you know the answer to.