Third Person: Prince of Persia Warrior Within.
FPS: DOOM, Quake, Unreal and yes Halo Reach for it's extremely inventive game play.
RPG: Morrowind.
And yes Halo is revolutionary in a sense, actually more evolutionary than revolutionary.
We have our gay ass standard fps with your standard controls, Jump, shoot, sprint, crouch which appears in Call of Duty, Red mercury, black hawk down, Battlefield, and many others. Now we have Halo Reach, which has Low-grav, Jumps, shoot, sprint, and crouch, Loadouts, that completely changes up combat, from small weapons to large vehicles. The fact that the physics are completely different compared to any other fps is quite revolutionary itself.