Camera you had the most fun with of all time?

Olympus PenFT: 1/2 frame (72+ shots per roll of 36); built-in meter; excellent selection of interchangeable lenses... and a 'native' vertical format! Also, the fastest sync for an SLR at the time.

The KMA2: First with a quality EVF; tilting viewfinder; best tele/wide accessory lenses ever (much too big, but super quality); 28-200 f2.8 G lens; 1:1 with Minolta CU filter; wireless flash etc.

Sony a900: Best viewfinder ever made; superb low ISO results; built-in stabilization; excellent combination of weight vs size vs performance. With no other A mount body sporting an OVF, certain to become even more appreciated in the future.