RocketSeason's right, the 80 would be a more stable system, but you need to resist the urge to fill up the empty space in the tank. Like atari and others said the surface area is much more important than inches per gallon. My advice is to get a LR
tower in there. Add some gobies or blennies to swim around and through the tower, and you will have a great looking system, along with some fish to swim in the upper area. The problem now is to find a lighting system that will fit in that size hood and properly mantain any corals you plan on owning.