I don't consider cheating fun. I play single-player for the most part, so if I were to resort to cheating, it would just mean I couldn't beat the AI. And that's pretty pathetic. I go out of my way to avoid guide books and manuals, too, especially the first run through. If it's the second time I've played, I may check a walkthrough to make sure I've done all possible quests, since I'm one of those freaks angling for 100% completion. But really, where's the fun in cheating?
And I see people here mention in modding, but it doesn't sound like anyone's using the cheat mods to then beat the game...just to rampage for a moment. Is it really cheating then? (I have a console, my poor PC can't handle games, so I'm pretty much out of modding for a while.) It sounds similar to me saving my game in GTA, killing everyone in sight before driving my car off the bride á la "Alias" and reloading to finish the mission. I don't really gain anything from it but a mindless stress release, and it never contributes to the way I finish the game. So...is it cheating?