From a roleplaying point of view, I\'m all for playerkilling.
Murderers and thieves are a part of every society, and a few of them lurking in the shadows would in my opinon add to the realism, and create an even better environment for roleplayers. But there is a huge difference between allowing players to kill other players, and to encourage that sort of behaviour.
The problem seems to be how to create balance in an artificial world, where there is no real consequenses to your actions. I\'m currently playing Dark Age of Camelot, and where playerkilling is \"allowed\" everyone roleplays a lunatic murderer. ;)
 I think everyone should have the OPTION to play an \"evil\" character, BUT they better be prepared to take the consequenses of, say, stabbing an innocent man in the back, on the town square in the bright of day.

I can\'t say I know a perfect sollution to this, but one thing that comes to mind is permanent death. For an example having the person dealing the first blow be blessed with a temporary perma-death-flag for a set ammount of time. Or even make the \"perma-death-flag\" faction based, with playerkilling (outside arenas or other PvP areas) setting the variable. Something to make a character think twice.

Just my 2 cents on playerkilling. PvP or no PvP - either way I\'m really looking forward to playing a mmorpg with focus on the roleplayers.