dtgreene: To me, for something to really be cheating, it either has to involve something that's labeled as a cheat code, or involve actually modifying the game's code or save files. (This means that, for example, I would consider using mods like the Fixpack or Sword Coast Stratagems to be technically cheating, even though they wouldn't make the game much easier (and SCS, to my understanding, is intended to make the game *harder*).)
I cleave to a fairly similar stance, although for me player-installed mods are fair game, since you have to go out of your way to acquire them and you know what you're getting into. In general I divide such issues into Bugs, Exploits, Min-Maxing or Cheats.
Bugs are issues where the game is not functioning according to the rules, whether as a result of developer error or deliberate player action. An example might be, for instance, casting a spell from a Wand while the game is paused, but if the player swaps out the Wand in inventory before unpausing the game, it casts the spell from the old Wand, but it does not deplete any charges. Since Wands are always meant to deplete a charge when used, this is an obvious bug and should be fixed.
Exploits can partially fall into the first category if they make use of a bug, but I also categorize exploits as players making use of NPC behaviour that, logically, they should not be doing. Examples would be the classic BG1 Drizzt cheese method of dismissing your party members in such a way so that they all surround Drizzt, and then attacking Drizzt with ranged weapons, who will then simply stand in the middle doing nothing as he can't walk through the neutral former party members. An alternative example might be casting a Cloudkill spell into a room, then shutting the door, upon which the enemies will happily sit in the Cloudkill spell until they die. In both cases, it's obvious that the strategy would not fly in a tabletop game. However, I don't necessarily think that exploits need to be fixed, as they typically require deliberate action on the player's part to achieve and players who crave a proper encounter (like defeating Drizzt in a fair fight) can simply not make use of these exploits. The experience is limited to the player's own game.
Min-Maxing is a bit of a tricky subject, since I know there are players for whom min-maxing is a source of great enjoyment. (The caveat of course is that one person's min-maxing might also mean another player's complete disempowerment. I've played in tabletop games where min-maxers basically made themselves SO powerful that the non-min-maxers were basically reduced to being window dressing in encounters.) There are certain combinations of classes/spells/items that are borderline broken, and that, if I were the DM at the table, would outright ban from use for being too disruptive to the game. However, that's not my call to make here, so my stance is that it should adhere to whatever the current rules+errata is for the ruleset in question.
Cheats are very similar to exploits, except that they are exploits that go above and beyond intended game behaviour, such as giving all of your characters 25 in every stat, 100% Magic Resistance, etc. Much like exploits though, in a single-player game I feel that you can do whatever you want to alter your own game experience, as long as it doesn't affect anyone else's.
