There was a free one I played for about a week till it got insanely boring but Silkroad Online
is something good for someone who doesn't want to spend anything.
It's not nearly as good as others you pay for though. But as I said it was fine for me, typically a non MMOPRG kind of guy for a week of obsession.
It really was awesome and I think I got up to level 27 but then it just starts feeling old.
EDIT: As for the next blockbuster MMORPG? I have no clue. I just want Blizzard to get Starcraft Ghost finished and SC2.