EVE online is one of the "F2P" games that you have to pay to do well. Similar to SWTOR.
I highly dislike WoW, for so many reasons it's not even funny. Guild Wars 2 is cool, and has a lot of stuff put together in neat ways, but has a lot of frustrating aspects to it as well - I didn't find it worth the $60. (iNathanLite, it's cool, but it's not a new things for MMO's.)
So far, the only MMO that's kept me enthralled is Dungeons and Dragons Online. It's not what it used to be, since they changed the learning curve WAY down to be new-player friendly, but it's still a fun game that you can get through without paying a cent.