I take a rather pragmatic view on cheating... If the fun from the game is being sucked out by being stuck at some particular point, I will cheat however much I have to.
A case in point would be the game Disgaea for the PS2. Absolutely HILARIOUS tactical RPG with exploding penguins, a demonic senate you can bribe or just beat into submission, they even make fun of the Power Rangers. The problem is that it is a level grinder in the extreme. I think there's a possibility of 999 levels for every character. The first few levels are pretty easy, and you start thinking, "Pbbbbbbbt! Can I increase the difficulty level on this?" Then you get to the first boss level, and get your arse handed to you on a silver platter. So you have to keep replaying the same couple of filler levels over and over again to level up your characters. I don't mind replaying a level once or twice if I'm under-leveled or just make a stupid move, but that kind of level grind just doesn't do it for me. So I will absolutely fish out a cheat to speed up the leveling process so that I might only have to replay a level 1-2 times before my characters are leveled up enough. There's also the fact that it costs money to heal characters, and that almost always eats up everything you get from a level, so you have no money for improved weapons or armor. That also takes the fun out of it for me, so I have no problem giving myself essentially unlimited funds.
Of course going the other way, if I made myself invulnerable and able to spam special attacks, then there's no real challenge in the game, so I won't do that.
On single player games, I don't care if people cheat or not. Whatever makes the game more enjoyable for you. That's kind of the point, right? Games are supposed to be fun. Multiplayer I'm very anti-cheating, unless it's like WarCraft 3, where if you cheat like giving yourself instant builds, the enemy gets the same ability. It should be a level playing field.