A brief list of features, mechanics, and other various and sundry design decisions that contribute to Guild Wars 2 turning the MMO genre on its ear.  In no particular order.

1.  No Quest Journal

That's right, the MMO staple quest checklist is gone, replaced by an elegant system of location-based public quests and events.  Wander into an area, help out an npc, your reward is in the mail (literally).  Most of the time you don't even need to speak to the quest npc to participate.  Removes the 'day-planner' feel from game time.  Anything that makes my game feel less like it was designed by Stephen Covey is a victory.

2.  No healers (or everyone's a healer, however you want to look at it)

Every character in Guild Wars 2 has their own heal – multiple heals in fact, though you can only have one on your hotkey bar at a time.  There is no one class that is a dedicated 'healer'.  This change alone revolutionizes the genre. Gone are the days of 'Well, we'd like to run a dungeon, but can't find a healer", or "I know you can't solo for crap, but at least you're good in groups, right?"

If you're one of those players who has convinced themselves that you enjoy playing UI Whack-a-mole in raids, well, give this new system a shot.  You might just find there's a whole world out there beyond the raid frames.

3.  Combat reaction times matter

Remember all that time you had to get out of the fire on all those WoW raids you ran back in the day?  Imagine that cut by like 75%.  In Guild Wars 2, when you see a ground effect, you have to move, like now.  Of course, this isn't a problem, because when you double-tap a movement key, you DO A BARREL ROLL!  Ok, maybe it's not actually a barrel roll, but it is a roll, and you do have to use it to maximize your combat effectiveness.  Walls of fire, arrows raining from the sky, giant meteors smashing to the ground…these things hurt, and without your trusty roll, you will die.  Probably a lot.

4.  Pay once, play forever

A major MMO that doesn't release with a subscription fee?  Heresy!  For $60, you get the complete experience with Guild Wars 2. Cosmetic and Quality of Life features can be purchased separately for 'gems'.  Gems can be purchased with cash or in-game money.  Lots of time but little cash?  Buy gems with gold.  Lots of money but little time?  Buy them with dollars.

5.  Join a guild.  Join that guild too.

A far cry from the original Guild Wars' account-wide guild membership, Guild Wars 2 allows each character to join multiple guilds.  Read that again – not multiple guilds per account, multiple guilds per character.  A character can choose to be 'represent' only one guild at a time, contributing to that guild's progress at the expense of the others.  This means that any given player could potentially be in a more 'hardcore' PvP guild with like-minded players, then hang out in a more laid-back family-style guild with their spouse or kids on the weekend, and since playing with guildmates accumulates guild influence at a faster rate than going solo, there is real incentive to do so.

Guild Wars 2 bucks MMO tradition and is a better game for having done so.  I had a blast during the head-start weekend and look forward to the the fun for a long time.  Anyone else enjoying the new MMO revolution?