Favorite length?
Now that's a toughie!
For CCW, well, since I live in a state that still doesn't permit CCW, I'll have to say that for my ccw-style gun I'd go with a three inch. Perfect balance of size and concealability, with better ballistics to boot! I have a 3" .38 snub, but wish I also could find a stainless three-inch 44Spl.
For casual plinking, my Dan Wesson wears its 4VH or 6VH barrels (VH = Vent rib, Heavy or underlugged). For serious target use, or for hunting, it wears a 8"V.
Let's see, the Blackhawk has a 8-inch, the .22s have 6-inch....