For a catch-all rod, a 9ft 5wt is hard to beat. Great for learning how to fly fish on!
For where I fish and what I target, a 7-foot 3-weight rod seems to do me great. I generally am looking for bluegills, and some spots require "tight quarters" casting, so the shorter rod helps.
I recently got a glass 7-foot 5-wt and am now addicted to it, but we don't need to open up that can of worms here!