I second that, the vanilla Frog is an absolute joy to fly!
Others I really like to fly are F-5E, Mirage, P-51D. I must confess though that I fly them like an airliner, I almost never search for the flight boundaries and keep it very safe.
Viggen seems a future winner to me, but FM isn't final yet so I shouldn't include it here. At the moment turn performance is abysmal.