I can't do this without dividing it into categories:
1) Favorite fish to hook for fight: Tie between wild RT and smallmouth bass in flowing water.
2) Favorite fish for the surroundings where it is usually found: wild brook trout. Makes up for the fact that they, IMO, are inch for inch the most anemic fighters of any trout I've ever caught.
3) Favorite fish for strike shock: Northern Pike
4) Most powerful fish in fresh water as a function of size: Bluegill
5) Best eating fish: Walleye, crappie, grouper.
6) Prettiest fish: Tie: West slope cutt, some brook trout (depends on the strain and location) and some eastern freestone wild RT (again depening on individual fish or location).
Favorite overall fish: wild brown trout. Not the winner in any of my categories, but scores high enough in all of them to be the overall winner. Adaptable, a good fighter, pretty, usually (but not always, of course..) found in pleasant surroundings. Without them, this thing we call wild trout fishing would be very much diminished..