Definitely a happy medium. I do make sacrifices for my daughter, but they are big ones and she doesn't know about them yet - she'll probably only realised as an adult herself. Anyway they aren't really sacrifices if you choose to do them. I work hard to make sure DD has as many advantages as I can scrape together for her, and I've been quietly shrewd and calculated when making some decisions for her benefit. But again, she knows none of this and she doesn't need to be aware. That's for the adults to worry about. There's nothing worse than a martyr mummy who spoils their child constantly while making them feel guilty and bad that poor Mummy isn't getting a minute to herself because she's had to go out to the shops again to buy Jimmy's favourite brand of ham for his lunch.
DD is a sensitive child, and we haven't always had money, so sometimes she'll say (about a school trip for instance) "but is it OK? Are you sure it's ok?" and I'll say to her "yes it's ok, if we couldn't afford it you wouldn't be going, it's as simple as that" or "if I didn't want to do it, I wouldn't". My parents had this attitude with me, and I think it's spot on. I knew I was loved and cherished. And I knew if I really wanted something, I could ask my parents for it and chances are I would get it, if they could manage it. If they couldn't, they'd explain why - no money because of car bill, no room for a puppy etc 
Mum and Dad have a great marriage and they always made time for each other. I'm glad they did, because they're still happily together and I have a great relationships with both of them - when I think about it,most of my similar age friends have divorced parents who split up when the youngest went to uni.
I try to follow their example in my own marriage, and I think it's paying off. I wasn't put on this earth to be a joyless, self sacrificing martyr, neither was my mother and neither was DD. If someone shot at me with a gun, my mum would throw herself in front of me, as I would for DD. She's travelled miles in the dead of night when I was very ill and needed her. I can depend on her for anything. But she never felt the need to deny herself a dress from the Next sale and a meal out with friends because it might otherwise deprive me of some daft piece of tat I longed for at the time.
I would hate my smart, wonderful DD to turn herself into a slave to her husband and children, so I'll always try my best to model the opposite. She sees me having fun with other adults, she's absolutely been packed off to her grandparents so DH and I can have a weekend away, and damn right I'm going to spend some of my hard earned wages on makeup and clothes when I need them.
Why the fuck would I want her to feel responsible for me turning into a drudge who never gets a break - that's a horrible thing to put on a child. Also I absolutely agree with whoever said that raising children to have their every wish fulfilled is going to stress them out massively in later life. Children need to learn emotional resilience and self care, and their first teachers in that will be their parents.
It starts young. Case in point, a friend of mine has a very miserable, entitled daughter who is becoming increasingly hard work. I could see it coming.. Aged three, I would be sitting in soft play waiting for my friend.... No show. I'd get a phone call "I can't come, Jessica won't put her shoes on"
Well, tell her to put them on, make her put them on, I'd say
Friend would say no- "because she doesn't want to"
So the child would dictate the whole day over a whim, and my friend, bless her, who was a loving mother and thought she was doing the right thing, was convinced that a three year old saying "I don't want to" was an unarguable, set in stone statement that a parent must follow at all costs.
Sometimes it's absolutely fine to "pull rank"