Guildwars, no monthly payment. Although if you buy the expansions when they come out it ends being one. Seeing as they come out every 6 months. You start out with 4 char slots, then you add 2 with each added expansion.
Decent - PvE (Player Vs Environment) The first part of 3 alone can give you well over 240hrs of gameplay before you've done just about everything with one Character.
Fantastic - PvP (Player Vs Player) Although if you plan on doing this be prepared to have to buy all 3 expansions because most of the skills are necessary for the latest builds
WoW - Cartoony graphics like Warcraft 3 but much better and the gameplay isn't at all like WC3, atleast from what I heard it isn't.