visually speaking, I'm not very fond of overally SD and moe character designs. All of my favorites, like Ghost in the Shell, Cowboy Bebop, Paradise Kiss and Princess Mononoke use more realistic designs, which I find much more interesting and are much harder to pull off, especially on a limited budget that most tv anime has to work with.
It is good, though to mess with things a little bit. Azumanga Diaoh being a great example of that.