Mercy?

One of the topics that I continually wonder about in (especially) fantasy RPG's is:  What do you do with an enemy that surrenders?

Okay, so you fight a gang of X (goblins, orcs, human tribesmen, human outlaws, etc).  At a certain point in the fight, the boss is dead (or maybe a sub-boss), and the remaining mooks all throw down their weapons and surrender.

Question 1: Do you accept their surrender, or do you simply slaughter them where they stand.  It doesn't seem very heroic to kill people who have surrendered to you.  Definitely doesn't seem "good", or "lawful".  I know a lot of players like to play neutrally aligned characters, and aren't constrained by such concepts as good or evil, but to me it seems a bit distasteful to simply "kill them all and let Pharasma sort them out."

Question 2: You've accepted the surrender of the mooks.  You've interrogated them, but they refuse to give up the information you seek.  To what extent do you use coercion to secure the information?  Do you intimidate? Do you torture?  At what point in the interrogation sequence do you cross the line from hero to villain?

Question 3: Okay, so you've wrung out all the information that you possibly can from your captives.  You are miles from any town or form of civilization, and cannot spare the time to take them any authority.  What do you do with the prisoners? 

• Let them go?  Well, they might rejoin the big boss and you will just have to fight them again later.  
• Kill them now, after they've surrendered?  It seems to me that there is an implied responsibility not to kill an enemy whose surrender you accept.  (Maybe it's just me, but that just seems like a "dick move"). 
• What I always argue for, and what always seems to get people to look at me funny is to simply cut off their thumbs and release them.  You've pretty much guaranteed that the enemy will not come after you later, while still leaving them able to have a reasonable chance of living out a life, albeit a somewhat harsher one.  I read Bernard Cornwell's Agincourt recently, and in it, the english archer protagonist  is captured by a french lord.  The lord lets him go after taking the little finger of one hand.  He made a point of the fact that he wasn't even taking the index and middle fingers, so that the archer could still function as an archer.

I'm not certain that there is a "best" answer to any of these questions, but they are ones that I think about whenever I'm in the middle of a fantasy setting battle.