6'4", 300#. Proportional torso/leg length, those with long legs and shorter torso or vice versa may have different results.
Most comfortable planes I've flown:
Mooney: M20J, M20R. Al Mooney was 6'5" and built himself an airplane.
Cessna: 182, R182, 310.
North American: P-51D Mustang
Piper: PA32R Saratoga/Lance, PA34 Seneca, PA24 Comanche, PA30 Twin Comanche, PA23 Apache/Aztec
Average:
Boeing: PT-17 Stearman
Cessna: 172, 180
Evektor: SportStar
Piper: PA28 series
Diamond: DA40. FWIW, I fit fine in a 2006 model that has had the canopy replaced with a 2008+ canopy. Legroom was lacking in the 2001-2 models, increased in 2003 and again in 2004. Canopy was redesigned for increased headroom in 2007 with the DA40XL. I'd be OK with an in-ear headset with the short canopy.
OK, once you're in the cockpit:
Beech: King Air 90 and 200
Cessna: 400 series
Extra: 300L. Had trouble getting my knees under the panel on the way in/out.
Hawker: 800. Just had to step over the console, so not bad.
Piper: Malibu series (one of the toughest to get into), J-3 Cub, PA18 Super Cub (All the Cub variants, incl the CubCrafters ones - Sit on the very aft end of the door sill. Swing your legs in, pull yourself into the seat using the frame tubes.)
Citabria
Husky
Tight Squeeze:
Beech Bonanza/Baron - Due to the rounded upper cabin cross section, I bump my head. A lot.
Blanik L-13 - I'm sure someone will post pictures of my first attempt to do this.
Went in the back seat which worked OK.
Forget it (Tried to sit in these, couldn't fly them):
Cessna 150/152 - Knees in the yoke and on the throttle with the yoke level and throttle at full.
Diamond DA20: Would have to lop off the top 4-6 inches of my head to get the canopy closed and my neck straight at the same time.
Columbia 300: Sitting in the left seat, I was looking at the upper curve of the door frame. Nope.