So much that is wrong in other games/MMOs is right in Guild Wars 2. From the pay-once-play-forever model (instead of forking out a ridiculous amount per month even when you're not playing) to the artsy graphics, to the way players help each other out rather than stealing each other's kills (anyone who contributes gets credit and loot), to event scaling and player scaling, to PvE, PvP and WvWvW (large-scale PvP with three servers pitted against each other), to dynamic events rather than grindy compulsory "kill ten rats" quests, the game tries (mostly) to let everyone play the way they want to. Oh, and it has a nice learning curve, too, with new features gradually unlocking as you level up rather than overwhelming you from the start. Plus the "Living Story" continually delivers new content so the game isn't anywhere near over after you've completed your personal story. Wow, I sound like an advertisement… they should pay me for this
Granted, some things could be better (the way "dailies" work changed recently, and not for the better in my opinion), but overall, it's a great game, and at that ridiculously low price, you can't really go wrong (40 USD at the moment, sometimes half that).