I hate tall tanks so I would go with the long and narrow one. I don't like narrow tanks either so if it were me I would go with a 180 gallon tank instead. I'm not a fan of overflows either since they take up room in the tank. Plus you can easily build your own that would function just as well or you can just use canister filters.
By the way, you can find AGA standard tank dimension here http://www.all-glass.com/products/aquariums/index.html
By the way, you can find AGA standard tank dimension here http://www.all-glass.com/products/aquariums/index.html