The Rules of Engagement

In order to maximize my engagement with the story and optimize my role as a moral agent, I have developed a handful of rules to guide this playthrough.  They are divided into two groups, gameplay and moral, and are more descriptive than prescriptive; I follow them most of the time, and indicate in my posts instances in which I deviate from them significantly.

Gameplay Rules

1. Limited use of the save-reload: The ability to endlessly reload takes away the sense of consequence and permanence required in order to act fully as a moral agent.  Although I am an obsessive saver, I try not to reload except under the following conditions:
1. PC death: Obviously, if the PC dies permanently, the game is over, which defeats the purpose of this whole project.  Moreover, the game reloads automatically from the last save point anyway.
2. Quest failure: If I fail a major quest objective through ineptitude (rather than by choice), I will reload.  I am interested in decision-making, and quest failure tends to cut off the sequence of decisions.
3. Negative outcomes due to experimentation: At one point, while I was overburdened with loot, I dawdled at a Word Wall while trying to figure out how to get down the steps and back to my horse.  When I finally stopped fooling around, dropped the extra loot, and found my horse, I discovered that a pair of sabre cats had already killed him.  Because the horse's death was a direct result of a gameplay failure (wasting time trying to overcome the encumbrance system) and not a result of a PC decision or failure, I felt justified in reloading, heading down the hill at my normal rate, and arriving in time to save my horse.  Later in the game, the same horse died during a Forsworn ambush; there were no extraordinary gameplay issues and I fought in my normal manner, so I did not reload, and had to obtain a new horse.
2. Limited use of the wikis: Wikis, while helpful, tend to act as spoilers.  In order to make real decisions, I'd rather not know what the "right" answer is (if one even exists) until after the fact.  Furthermore, as a stranger in Skyrim, my PC probably would not have access to encyclopedic sources, so it seems more immersive for me to limit my access as well.  After I complete a quest, however, I do explore the relevant articles to find out what I may have missed.

Moral Rules:

1. Killing: In a combat-based game, violence is the norm, so most of the in-game ethical dilemmas will involve decisions about whom to kill:
1. Hostiles: In most battles, Skyrim does not offer a "subdue" option, so I feel justified in killing any creature or NPC that attacks me without provocation.  This has led me into some troubling situations, such as killing members of the Forsworn or the Afflicted, even though I'd really rather not.
2. Unsuspecting "bad guys": Bandits prey on the innocent and necromancers are always involved in some kind of abomination -- not to mention the fact that both groups always attack me on sight.  Therefore, sneak attacks on these types of groups are usually justified.
3. Wild game animals: While I don't typically go out of my way to hunt, non-hostile wild animals drop valuable resources (hides, meat, petty souls), so as long as an animal isn't owned by an NPC, I feel justified in "harvesting" deer, goats, foxes, rabbits, and fish.
4. Thalmor agents: Although I haven't finished the main questline yet, I'm reasonably certain that the Thalmor are the root cause of Skyrim's problems, including the dragon attacks and the civil war.  Even if Thalmor agents don't attack me first, I still feel that their machinations are destructive enough to justify my killing them.  Also, if I'm being honest with myself, their outright sneering racism and gleeful repression of Talos worshippers makes killing them more of a pleasure than a chore.  Perhaps I should feel more conflicted on this one, but I don't.
5. Vampires: Most undead (draugr, skeletons, and zombies) fall into the "hostiles" category, but vampires are a bit different.  First, even though they are considered "undead" for purposes of undead-related spells and weapons, they are actually NPCs suffering from a disease rather than mindless automata.  Secondly, the ones I have encountered so far are all classically villianous and usually carrying out some kind of larger plot (see the post on Laid to Rest).  Therefore, my general policy is to kill them when possible, but there are some limits (see the post on Hitting the Books).  Obviously, the Dawnguard questline, once I start it, will affect my views on this category.
6. "Special Cases": There are a few situations, such as the random encounter the Old Orc, in which killing is uniquely appropriate.  The Old Orc wishes to die honorably, so he asks if I will help him by fighting him to the death.  I have no quarrel with him, but because he clearly wishes to die with honor, killing him in battle is justified (and perhaps even virtuous, from the orc's standpoint).
2. Stealing vs. Taking: The game draws a clear distinction between stealing and taking by indicating items that can be legally taken with a white "Take" caption and those that cannot with a red "Steal" caption.  Stolen items can only be sold to the fences who work with the Thieves Guild, and a bounty is incurred if anyone witnesses the theft.  The game mechanics, however, do not cover the full range of possibilities:
1. Stealing from enemies: Stealing from an NPC I feel justified in killing seems to be likewise justified.
2. Stealing from neutral NPCs: I try to avoid this unless it is necessary, such as completing a quest that helps to prevent a greater evil.  To be honest, the NPC's disposition toward me matters more than I can morally justify; if NPCs are rude or dismissive, I feel less guilty about stealing from them.
3. Stealing from friends or allies: There must be a very compelling reason for me to do this.  As far as I can recall, I have not stolen from a friendly NPC.
4. Taking from enemies: Obviously, if I am comfortable stealing from a live enemy, looting from a dead one is justified as well.
5. Taking from neutrals, friends, and allies: This category varies greatly from instance to instance.  In some cases, friendly NPCs directly offer some of their belongings, so there is no moral conflict apart from a minor misgiving that I might be taking advantage of a friend's generosity.  In other cases, even though an item is marked "Take," it seems more like stealing. 
6. Taking from barrows, burial chambers, etc.: Dungeons full of draugr often contain valuable loot, but the lore suggests that these items were left in honor of the dead buried there.  I routinely take these items.  Even though I am trying to play a religiously orthodox PC, I find it hard to justify leaving useful items in a tomb.  Furthermore, these places have already been desecrated, as evidenced by the presence of the draugr themselves.
7. Taking from shrines and temples: My behavior in these places depends almost entirely on the focus of worship.  Although religious tolerance is a virtue, most of the Daedra are nefarious entities, and their followers likewise, so I have little problem ransacking their unholy places.  Sites devoted to the Divines, however, I generally respect.
3. Other NPC interactions: Although most game time is spent exploring and fighting, dialogue with NPCs is a major component of Skyrim, so a few guidelines are in order:
1. Response options: When given a choice among responses, I usually choose the most polite and respectful option.  It seems to make little difference to gameplay, and it is in keeping with the kind of PC I am trying to run.
2. Miscellaneous quests: When an NPC asks me to complete a miscellaneous quest, I usually accept, unless the quest goes directly against my own sense of right and wrong.  Again, I want to run a beneficent PC, so helping the citizens of Skyrim whenever possible makes sense.  This habit sometimes leads me to have too many open quests -- a problem I usually have in the real world as well.
3. Persuade/Intimidate/Brawl/Bribe/Lie: In some interactions I am required to convince NPC to do things they'd rather not do.  I usually try to Persuade, but if that fails, I might chose to Intimidate or Brawl (if available); violence or the open threat of violence seems slightly more honorable than the more underhanded Bribe or Lie option.  It may seem strange to prefer the violent options over bribery, but since virtue in this setting comes from valor and honor, beating up an NPC feels less "evil" than paying him to do something he shouldn't do.  Still, I would not be eager to defend this point in a debate.
4. Hold Guards: I try to avoid incurring bounties, but when I am stopped by Hold Guards, I will typically try to talk my way out of getting arrested (using my status as Thane, if applicable).  Failing that, I will pay the bounty.  With one quest-related exception, I have not yet been arrested; if I were to be arrested, I would not resist.  Since I am playing a mostly Lawful Good kind of PC, fighting with the guards is hard to justify.

As I mentioned the the beginning of this post, these rules are not the Ten Commandments; I have broken most of these at some point. In fact, I would argue that the instances in which I have deviated from these guidelines have provided some of the most morally compelling moments of my gameplay.