Personal I don't like any cheating because that blow away ALL the Fun etc I have .... playing a game !
I agree to an extent - certainly playing a game on 'god' mode takes all the fun out of it - the only time I ever use god mode is when I've tried the same sequence again and again and I keep dying (and there's no option to go back and re-spec or improve my character). In that case, it's the constant dying that takes all the fun out of the game, and a minute or two on god mode makes the game fun again.
As for other cheats, I try never to cheat first play through. I certainly didn't need to cheat on DKS - I would have liked to cheat on that annoying final zeppelin escort mission, but unfortunately making myself invincible made no difference - and judging by the consensus on these forums, most players would have liked to cheat through that extremely annoying mission.
But if I'm playing a game for a second time, I don't want to have to re-search every nook and cranney, or re-do every side-quest, so I will usually boost my cash and stats as necessary to make up for the bits of the game I skipped. E.g. in my second play through Dead Space 2 I simply gave my character $1 million at the start, then bought all my equipment rather than searching through every box and secret area again.
It's definitely a personal choice, but one that should be left up to the players rather than the developers - I've given up on a number of games in the past because they just got too hard at a certain point (the final levels of Phychonauts springs to mind, although I did eventually finish that one without cheating - after about 50 tries...).
