I know that I'm very privileged in that I could afford to live at a higher level than what we do, but I don't want that. I've got my American dream. I've got a wonderful wife who dotes on me (it's mutual), a small house in a quiet town, and a cat. That's all I really need in life. All the other shit (gadgets, new cars, etc.) is cool, but I realized about 5 years ago that none of it made me happy.
If we have kids, of course those expenses will go up, and we'll probably have to find a bigger house, but for now, we live cheaply not because we have to, but because expensive stuff won't make us happy.
(Just to be clear, I know what it's like to be poor, I grew up in a very poor family. I very much realize that I'm lucky and more fortunate than a lot of other people in that I have the luxury of living below my means, a luxury that not everyone has, even in the US).
Even in Seattle, I know of married couples who spend under $2k a month total, inclusive of rent, utilities, eating out, buying random stuff, etc while earning north of $120k each. Sure, its a meek lifestyle, but it can be quite fulfilling to know you aren't a consumerist whore.
If money = happiness, you are apt to lead a really sad life!