Ka0s, it depends upon the mods that spawn. It varies between 101%-200%, depending upon the difficulty level. As difficulty goes higher, I've found my mods tend to be lower. Like in Hell level, people tend to Chicken like crazy thus reducing my odds of getting 200% fun. In Normal, it goes up because people tend to be untwinked, are leeching their way to NM, and they haven't considered resistances yet. This is when I get a 200% modifier.
Also, there is a bonus to the "Happy Thought" mod. This is the modifier that gives you the satisfaction of knowing you just ruined somebody's day. Just the mere thought of them exiting and cursing you adds an extra 50% to the fun mod. It gets higher in each difficulty for every successful PK. This can help the fun mod because of the Chicken Modifier. So instead of rolling 101% fun, you get 151% fun. But because you are not always successful, it will give you a weighted average dependant upon tries vs. success.
So, for each person it is different. Don't forget to socket your Helm with a "Jewel of No-Conscience" or the most desirable Perfect "Ruby Jewel of No-Conscience"... the latter adds 40% enhanced desire to PK with No Regard.
