I am one who loves the look of sand myself. I have considered the benefits of running "bare-bottom", but I just can't seem to get past the (oldschool?) idea of not having some form of substrate in my aquarium's! It's a personal point of view thing.
I used to make my sandbed's around 4" deep give or take, until recently... now I like to run less. If the aquarium uses plastic trim, I like to use just enough sand to bring it to trim level.