The only 'decent' free one I know of is Archlord (it used to be subed) but from what ive heard its pretty grindy and distinctly average, I played the beta for a while and it was okay.
If its just for a few weeks, quite alot of MMOs now have a free 14 day trial, if your going to be buying Eve you can use the 3 week free trial now and then buy the game at the end of it if you've got the cash free.
EDIT: oh yeah anarchy online, think the free version is the core pack without expansions + in game adverts.
Been tempted to try out WURM myself, sounds really interesting from the stuff I've read about it, but scary in terms of what can be done, both by you and to you.
Runes of Magic is awful. They've tried to blatantly copy the WoW style of graphics and gameplay, but with none of the talent or soul of WoW's design. You're also constantly bombarded to buy stuff from the shop, it completely breaks the immersion.
Guild wars as someone always points out in these threads, is 100% instanced. Good game, but only with a regular group of friends.
You could try out the US version of dungeons and dragons online, that recently went ftp with an optional sub. There are some pretty severe limits with the free version though, and again you get bombarded to either buy stuff or take out a sub.
If you can stretch to it, you can pick up lord of the rings for about €8, and 60 day game time cards cost €15, which is silly cheap for such a quality mmo.
I've been advised to check out Armada Online by a mummorpagger primo, Quantra - normally he's into the isometric jap style, Thang and most certainly Ragnarok, but he's not limited. Pirate King was fun for a while once you got past the awful graphics, but I only played a few months of the alpha and it seemed to be a game rife for the member's market trade. That's what ruined Thang for me, being totally impossible to progress without 99 pot stacks purchased with actual cash. However, he (Quantra) has high hopes for Armada Online, and I'll be checking it out as soon as I've shouted at enough BT employees to get my internet working at a respectable speed.
I used to play ragnarok... grown out of that. I've seen alot of korean ones but there all the same to be honest. I don't mind grind just like to have a good combat system and what not about usually a bit dull in that respect. I'm at college the now though. lol