Cap, I had a 180g (6'x2'x2') and now I have a 125g (5'x2'x20") and I like the shallower tank much better.
Have you ever built a tank before? Are you putting anything besides wet silicone between the panels? Are you setting the side glass on top of the bottom glass or on the outside of the bottom glass? Are you using a frame or euro bracing or just thick enough glass to go rimless?
I've built 5 tanks over the last 4 years and doing one that big still scares me. I'm just finishing a 2'x2'x20" 50g tank and in the past I've done 3 for me and 2 for friends. I have an old 180g that leaked and I'm planing to tear it apart, clean it up and reassemble it with a euro brace.