What about the Handhelds? The "famous" Razor Switchblade with "customizable buttons" depending the game is in fact a very old idea: the MILTON BRADLEY MICROVISION used to have that: each game hold its own series of action buttons. And it used to have one of the best controls for sliding games as Pongs, Arcanoids, etc: a jog dial . So in handhelds the first one use to have the best control for these specific kind of games.
Then the Epoch Pocket Game Computer introduced the modern style joypad that will be used for most handhelds: Game Boy, Game Gear, Atari Lynx.
In the handheld world the last world in controls of course is on Pandora: every the detractors must admit this: QWERTY kb, 2 nubs, triggers, and the pad that is great . Sometimes amazed about the nubs we forget that in fact the Pandora´s pad is EXCELLENT.
Before the Pandora in my opinion the GP32 and the NEO GEO POCKET were the 2 handhelds with the best joysticks , specially for fighting and arcade style games. The best triggers (i know i will surprise someones ) : the DIGIBLAST. The best buttons : probably the DS. The best triggers: GP32 again... these triggers round the console a little making push them very easy with the fingers a little rounded (the natural position)
Regards
Scara