It's all about the fish.. and by that I mean Healthy, well cared for, quality specimins. I guess I spent too much time in the horse show world.. but to me the health and over-all quality of the fish being housed is most important. not gonna lie some of my set-ups look like compleate junk. But I always get compliments on how healthy my fish are, by hobbyists and family/friends. I find it sad when I see a really nice set-up and the fish are all half dead, imo thats not a show tank. But a tank can look like it's about to fall apart but if it's houseing even a really nice and obviously unstunted, and well cared for Oscar.. thats a show tank to me... It "Shows" the fish is healthy, and obviousely well-cared for by a dedicated owner.
Of course if you can take that stunning looking tank, and house stunningly healthy fish = Money