Straight-up platforming: Mario. Just... Mario. Controls that are tight and precise, something that wasn't as common as you might think, back in the NES days, and when he went 3D, it was perfect right away.
First-Person Shooter: Doom and/or Quake.
On the other hand, the genre didn't evolve much, if at all, until Half-Life came along and revolutionized the genre; that is, there was a little more to the game than "run through a level killing everything on the way to the end, then repeat when dropped off in the next level". The Half-Life world, save for a few moments to load areas (no loading screen) was sweetly seamless, the characters you interacted with had real personalities, and let's not forget the awe-inspiring presence of the G Man.
Yeah... screw Doom and Quake, I'm lining up with Half-Life.
Action/Adventure: Zelda. For all the flack the series has taken in recent years for its apparent lack of innovation, it's still the reigning champion of the genre, and nobody can deny that.
Japanese RPG: Final Fantasy. For all the flack the series has taken in recent years for its innovation, etcetera etcetera. Seriously though, it's the measuring stick against which other JRPGs are measured.
Western RPG: Little harder to define, mostly because I don't know much about Bioware's earlier games. However, the first title that comes to mind would have to be Mass Effect. Someone kindly correct me.
MMORPG: World of Warcraft. Need I say more? Sure, it's hardly the first MMORPG, and some would say it's not the best; but simply for the staggering number of people who play it every hour of every day, world wide, it is undoubtedly the king of the MMORPG hill.
