You could try Infantry, which is owned by Sony. A 3rd person shooter game with various weapons and equipment. It's actually a game with games. there are different "zones" to enter that you can play, and one of the types is an RPG. Another one would be a map called DotA All-Stars by IceFrog from Warcraft 3: The Frozen Throne. Wouldn't consider an MMO that much, considering there can only be 10 players per game, but it's worth a shot.
Check that. I don't really know what defines a game as an MMO. If it's how many people play it, or the amount of max players you can play with at once. If it's the first one, DotA is definitely an MMO
i played wow for a few months got a 1 character max lv 2cnd character lv 75 then i did some endgame raidng and got bored... So i just spontaniousl quit i might play again when cataclysm comes out
RuneScape is good, if you want to try it out they have just released a demo mode so you can start straightaway. It'll put you in a tutorial but that only takes a few minutes and once you have played the demo to it's limits I'm pretty sure you can upgrade your account to f2p if you want to, without losing any levels...and from there you can upgrade to members if you want. I'd seriously suggest jsut trying it though, it's one of the most popular out there and you have othing to lose (except a little spare time =] )