Well, I would suggest Guild Wars to try. Its fun but for me got boring quickly (I'm not much for PVP.
I've played FFXI for 3-4 years and thats was pretty fun. But the game is dated to the point that I can't suggest over the new MMOs.
I "just" started playing LoTRO and so far, its my fav of the three. And I haven't even gotten past level 14 yet. I keep re-rolling characters and trying out the races XD I really really suggest LoTRO, the game is just, awesome. (Side note: early levels is awesome, can't say how mid-endgame is yet )