Could give a longer response if specific questions are asked, but since I'm pressed for time I'll keep this simple.

To be perfectly honest, my rule of thumb is usually to go with heavy realism in virtually everything I do involving writing. I'm not a fan of escapism in terms of the themes of a story or how they're presented on a psychological/characterization level. Now don't get me wrong -- I'm not saying that I'd showcase a brutal torture or rape scene in a story or role-play that's meant to be viewed by kids, but I'll never try to detach people from what's happening unless there's a significant reason.

Regarding death, or specifically killing given the premise of this thread -- I personally feel that it's better not to water down the emotional and psychological weight that the taking of another's life can have. My attitudes towards this sort of detachment is that they're generally unhealthy, and if people are going to write a character taking another life then - unless this character is a psychopath or something - it's only [i]realistic[/i] that the character would go through an ordeal from it. I dislike the notion of the escapist characters who can just cut down hordes of troops without batting an eye, especially if these characters in question are meant to be our protagonists.

As for monsters -- I usually consider them to be a cop out so the writer doesn't have to take responsibility for the moral and psychological elements involved with killing another, but it's an acceptable route in specific types of stories that obviously [i]need[/i] monsters or soulless opponents as the basis of their genre or lore. I've got plenty of examples of this in my own work actually, but I don't believe it's a justification to water down or neglect the realism whenever a human actually has to kill another of their own kind in the story and - unless a story is set in a very unrealistic world by default - it's highly unlikely that you won't encounter humans fighting or killing each other at [i]some[/i] point.

[quote=CyclicCynicism]Maybe the amount of detail you put into the act of killing and its impact shows the maturity of the player and of the game.[/quote]
[i]This[/i], honestly. If people don't go into the psychological details, it says a lot about them. In particular, it says whether or not they've got a mature understanding of the weight of what their character's done. You're not going to find someone who's killed someone writing a role-play where killing's written off like it's nothing, unless they're trying to escape past experiences anyway.

Edit: [url=http://www.roleplayerguild.com/topics/152118-how-do-you-write-what-a-character-feels-after-killing-someone-for-the-fir/ooc]This[/url] thread provides more discussion on the matter of writing about killing.