Guild Wars takes the best elements of today's massively multiplayer online games and combines them with a new mission-based design that eliminates some of the more tedious aspects of those games.
You don't have to spend countless hours on a leveling treadmill to get to the interesting parts of the game. You don't have to spend hours running around the world to prepare for a quest. You'll never spend days playing, only to discover that the choices you made early have left you with a permanently uncompetitive character. And you'll never meet new players only to discover that you can't play with them or compete against them because their characters are on a different server than yours or they have a different chapter of the game; in Guild Wars, all characters live in one seamless world.