If you don't want to pay a monthly fee, then play guild wars.
Guild wars is a fantastic idea, make a pvp focused mmo with no monthly fee. But is guild wars fun? If your into pvp and don't mind a few issues then yes, guild wars is a very enjoyable game. The one big factor to guild wars is even though the level cap is low (20) the game is jam packed with hundreds of skills. If your going to be of any use during pvp battles you'll have to learn your class and this is where the pve section of the game comes into play. The factions campeign is rather short ( around 10 hours) but it's the best way to learn how to play and how to use your class properly. Though it may sound easy, its actually pretty deep. You'll be able to pick a sub class and in doing this you creat a brand new class. You'll get skills from both sides of the mix and picking which skills to use can be a bit tricky, but there is nothing a little online guide can't help with. Overall guild wars is a great game and the fact that there is still a very strong community playing is evidence of just how great the game truly is.