I think when you first start playing Sims it's very tempting to cheat like mad as soon as you realize it's possible, it's like "Oooh, all the money I want, what's not to like?!".
But in fact I think it takes all the challenge out of the game = boring. I think you can really ruin the experience for yourself by cheating your way to all the goals and rewards in the game instead of figuring out how to do it the hard way. At least that's how it is for me.
Playing God and being able to do whatever you want is not as interesting as you might think.
However I have used a few carefully chosen hacks/mods in the past, usually to fix gameplay issues which were annoying me. That is: to make the game better and more fun, not easier.
For example in Sims 1 I had a whole pack of objects like toilet, shower and bed which were just a little faster to use than they were supposed to be. That gave my sim a little more time to do more interesting things. Also I had a stove which taught cooking when used like they do in Sims 3, in the first game I think the only way to learn cooking was to read about it which was just silly.
And when I started playing Sims 2 I was getting seriously annoyed with the insane number of friends sims had to have to get promoted in some carreers, I felt like the game was dictating how I had to play. So I used a hack to make my sims instant friends with everyone they met or something like that. That way a loner sim could get promotions too and I could play how I liked. I love how they've changed the promotion system in Sims 3, now I don't need that cheat anymore.
In Sims 3 one thing that's starting to irritate me is how the lifetime wish is so dependent on traits, I'd like to be able to mix it up.
It might be fun to have a kleptomaniac wanting to be a cop or an inappropriate politician with no social skills or an evil, insane surgeon.
And why should a Renaissance Sim be workaholic? The workaholic trait gives an advantage to sims with jobs but a renaissance sim needs to build lots of skills so might be better off not even having a job but instead doing things like gardening or painting at home. It makes no sense.
So I might soon be looking into a way of choosing the lifetime wish for any sim.
The Sims is not like real life though, in real life I would love a money cheat.