Check this one out:
http://www.mpogd.com/
It's a mmorpg directory
I have checked out every single free mmorpgs listed there bcause I was bored during the holiday and because I'm a mmorpg freak
They have some good ones in there I think.. a general guide is: go for client-based, and if the client comes in a huge file size then you are probably on the right track
Although there is this game called Conqueror or something which is poorly designed - despite the file size '-__-
Runescape is a classic
and it's probably ranked number 1 on my mmorpg list as the most time consuming mmorpg. Unless you are one of those odd people who are content with low levels or you happen to come under the blessing of some experienced players, you will be spending the rest of your life trying to level.. I find RS impressive only because it's web-based and has decent graphics (I'd give 3.5/10 for the graphics, that's pretty good according to my scale
). There was a time when I sat there and clicked on rocks for a few hours a day.. now I can see that it was insanity '-__-
Another thing you can do is to look for private servers (the best place to find them would be this:
http://www.gamesites200.com/). I'm not 100% sure if they're legal or not
but it seems that they are. Take RO (Ragnarok Online) for example, the most popular emulator is eAthena and it is released under GNU.. The RO client is free to download so I suppose that makes private servers legal
anyways.. if you decide to go for private servers, what you get is good game play + good graphics (as they're commercially developed games).. The draw back is that the gaming community will be very small compared to "the real thing" - which kills the purpose of playing mmorpg.
Basically, you will waste your time if you play mmorpgs. "been there, done that"
good luck