I played www.project-entropia.com for a while.
I found it heavy in RPG (which I disliked), the graphics are good, but outdated and it's free (you just download, create your character and join). At least for a while (ie, you can only get so far without depositing).
Its a massive world, unlike most MMORPGs its just one gigantic server with hundreds of thousands of people packed into it.
The reason I left is I found the community rather elitist and snooty. But you may have a different experience.
PS. FYI, I now play City of Heroes/Villains and I'm finding it rather enjoyable...excellent graphics and loaded with content...they also dominate the current MMORPG market. For a measley $14 ($20 in AU) a month its pretty good