Yeah, but it leaves a pretty small margin of error. Believe me, I deal with people all the time who are forced to sell before they originally intended to. Family, health, divorce, job relocation, etc. People say that its fine because they'll be there for a good ten years, but in reality, people rarely stay in the same place that long.

And I'm not necessarily saying you have to have 20% either... in CA (or even in Boulder) that would be plain-old impossible for most people. But you should have a pretty decent chunk, if not to put towards your down payment, then at least to have in cash reserves. For someone in a situation like red94teg, if you can make the payments, and you're comfortable with it, fine. Go ahead and put down a 5% down payment if it suits your monthly or long term needs. But be damn sure you've got another 5-10% in the bank somewhere because if you're layed off, injured or whatever... and you can't make your payments, you'll be out of options pretty quick.