My father instructed in Harvards (AT-6's, actually) but I've never had the chance. It was his favorite plane.
And I had the controls of a Spartan for a few minutes, Pigboat, absolutely delightful - you could roll with two fingertips. The Howard by contrast handles like a DC-3, very stable but gives you a workout.
I'd really love to fly a P-47 or F4U or F8F though. Spoiled on the R-2800, or any E. Hartford radial for that matter.