Throughout my gaming life I've used about 15 controllers from different systems, from the basic but classic snes controller to the bulky and clumbsy xbox pad. As controllers they all do fine and serve their purpose, but sometimes it's the little touches that can really make it stand out from the rest.
Take for example the z button on the back of the n64 controller that made it feel alsmost gun like, or the c stick on the gamecube controller which looked alot like a nipple. One thing I have noticed is that Nintendo seem to be the ones who take on new ideas and have really pushed the idea of a game controller along. Their latest game pad the wii-mote is something completely different and never used before in games, and for that I praise Nintendo (although I am not the biggest fan of the wii), they are always in search of new ideas rather that churning out the same old thing.
As far as my favourite controller goes, I'd have to say the PS2/3 (as theyre more or less the same) is the most functional, and you can see this from the way that it 'hasn't' developed much over the years. A close second would have to be the gamecube controller because it was just so damn comfortable. It felt like it was moulded to fit your hands, as if you'd pressed your hands into a ball of clay and made a controller out of it.
Looks though, is a different matter. The N64 pad was iconic, with its three handles almost looking like some sort of hybrid super-controller. The PS3 pad however, is a bit too industrial looking for my tastes with its perfect cricles and straight lines. But it shocks me to say that the xbox 360 controller is my favourite for looks, partly because I'm not a huge fan of it. I think it's the smoothness and curved contours that draw me to it.
When I look at the future of gaming I can see controllers moving more towards motion sensing, even though I do not think it enhances the gaming experience a great deal. Who knows, maybe one day we'll be able to hook ourselves up to a PS5 and let our minds be the controllers.