NOOOOOOOOOOOOOOOOO NOT Battlefield 2142, please dont buy that game with in-game advertising. Just settle for Battlefield 2, like said above NWN 2 is $25 at Best Buy which i just ordered. Guild Wars is great which im currently playing and no need to pay extra per month. Elder Scrolls IV: Oblivion which has gotten good reviews everywhere but i havent played it yet. Company of Heroes is good also. Half Life 2 and all the little expansions/episodes, Episode 1; Lost Coast; Deathmatch; Day of Defeat Source; Counter Strike Source
Battlefield 2 multiplayer FPS
World of Warcraft is a solid MMORPG, just wish I had the time to play it, I miss it greatly. $15 a month is not too much to ask for quality entertainment (or $12 if you buy time in bulk).
RPG? Oblivion, but that is only because I have not played NWN2 yet, I would be willing to bet that it is a better game.