If there is another bust coming, which I believe there will be, it'll provide some great buying opportunities for the smart investor. During the last downturn in the real estate market several of my friends made some great buys in places like Las Vegas, Florida, Hawaii and Phoenix.
Zero down loans are generally a bad idea for most people. But what's a really bad idea is when people borrow up to their maximum limit, plus go with a zero down loan. I don't have a problem with going with a 30 year mortgage, provided that you have a plan to pay it off early. Back when I had a mortgage I'd always make two payments per month. It's surprising at how much interest that cuts off your loan. I've also never paid more than 7 years on any mortgage that I've ever had. The "trick" is to come up with a plan and stick to it. And part of that plan is to eventually get out of debt and then stay out of debt.