Okay I got in here a little late so if there's anything here that's already been mentioned assume I'm just backing it up.
Mabinogi as Malkavian said is pretty great, I agree with his analysis. If you're looking for something different then I can't reccomend it enough.
As far as PvP goes RO is an older MMO (that is grindy as hell, admittantly), with full guild PvP and territory holding. But again, beware of the grind. It's been alive since the early 2000's despite being a massive grind for good reason.
I'm pretty sure I saw someone reccomend age of wushu, It's a goodun for the PvP types. Most anything meaningful in the game is based around PvP, and you should be ready to be assaulted physically for no good reason. Combat system initially seems mash the keys-ey but it's actually got quite a bit of depth. Read up the column, "Art of Wushu" on massively for a bit more info on the game.
Haven and Hearth, while focused more on building then PvP, is still an open PvP world, with a.... unique combat system. It's very complex, and not without it's flaws, but it works. Downside is due to it being more of a world building game complete with player thieves and brigands, it's got to maintain fear of outlaws somehow, and ergo it is possible to grind your troubles away. With the world resets that occur fairly frequently however, I doubt it'd be that big a deal. Also includes permadeath! You get back a portion of your stats and skills if you reincarnate depending on a particular belief slider, a lot of people on the forums are very weepy about the fact that this means the game isn't permadeath anymore, but it honestly has very little effect as most people will be on the low end of the "getting stuff back" spectrum, as it speeds up character growth significantly. Playing as a hermit is possible but most people would reccomend playing in a group.
I'm sure there are more but those are the ones I remember.