#1 Guild Wars 2
Released in 2005 to strong reviews, Guild Wars was a revolutionary game, so much so that fans argue to this day about whether or not it qualifies as a true MMORPG. Some aspects, like the combat system, seemed more at home in a strategy title than a standard MMO, and the pricing structure, which eschewed monthly fees in favor of episodic campaigns, remains one of the more unique approaches in recent memory.
Guild Wars 2, if you can believe it, promises to shake things up even more than the first game. Developer ArenaNet has reconsidered just about every convention of the genre, often with a novel solution as the end result. Traditional quests are out, replaced by a dynamic event system that responds to your actions. The system will move beyond a series of branching choices, instead organically building the story outward based on the ways you tackle your objectives. While it's an ambitious goal, success would pretty much eliminate grinding altogether, leaving you free to enjoy the game as it unfolds. Throw in new races and professions, a greatly streamlined combat system, a much higher level cap, and persistent PvP, and you've got plenty of reasons to be excited.