I agree with you that it is possible to have too much stuff, Grinity. Clutter is bad, and too much of even a good thing is just clutter. And I also agree that the child must hear no sometimes and you must mean it when you say it.
My point was just that you're not spoiling a child with stuff as long as you give it freely and without emotional pressure or manipulation, and as long as they love it. You might spoil your house, your storage system, your life! But you're not turning your child into a "gimme monster" because she has that 11th princess dress that you wanted to give her and for which she's grateful. I figure if a young child (say, under 6) says "thank you" without prompting at least half the time, that's a good sign that you've not spoiled your child. (I'm assuming that the other half of the time the child is *so* excited about playing with the toy that s/he forgets all manners! LOL!)
Our system for saying no: we started giving a small allowance and requiring small jobs at around age 2. These are two separate things--not payment for the job, but coexisting tools for teaching responsibility.
We say, "All members of this family have responsibilities. We all must contribute to the running of the household because we all live here. DS3, your responsibilities are to clean up your toys every evening, set the table and throw your clothes down the laundry chute. Because you are older, DS6, you must also fold your clean clothes, feed the cat, and help me keep an eye on your brother." These jobs are non-negotiable, just as DH's and my adult jobs are non-negotiable. We all contribute to making the household a nice place to live.
The allowance teaches fiscal responsibility as well as responsible choice. They have spending money of their own, so I do not entertain any toy requests in the store. I just flat refuse to hear it, saying only, "If you want it, bring your wallet with you and buy it. That's why you have your own money." (Though admittedly, I do still have to say this a lot more often than I would like!)
I do not edit their choices about what they do with ths money. The whole point is for them to have the chance to make mistakes with it. Better that they learn consumer skills when they spend $5 on a crummy toy that falls apart than that they wait until they've run up a $30,000 credit card bill (as one of our relatives did in college!)
YMMV, but our kids are much more choosy about toys when it's their own money they're spending. They rarely spend, and if they do, they use the heck out of that toy! The older one has already learned to save for a long-term goal and the joy of seeing his savings increase. The younger one is still pretty much Mr. Immediate Gratification, but he's 3. There's plenty of time.
And at least I have an easy "no!" for the "I want it"s at the store!
