Save for a down payment. It will put you in a better cash position in case rates go up. It's better to buy a home at a lower price and higher interest rate then a home at a higher price with lower interest rate, even if the monthly payment is the same. If rates go down you can refi, but your purchase price will stay the same. Also only your interest payment is higher, not your principal payment. Your taxes will be lower also. It's also better when you go to sell. You don't want to sell a home that cost you 600K for 500K even if your montly payment is low. Your cost basis is a lot more important than your monthly obligation.

You're assuming that rates are actually going to fall in the forseeable future. What if for the next say 10-15 years we have nothing but interest rates go up and up? Take your mortgage and imagine a 15% mortgage on that. BTW: if mortgages are 15%, can you imagine what the APRs on other financing will be like? Don't think 15% is possible, talk to someone that bought a house back in the early 80ies. 

I think the misconception some folks have is that they think home prices are going to have a sustained downward trend, but that mortgage rates are going to rise and then stay flat or even fall, when in reality, home prices are going to continue to fall, and mortgage rates are going to continue to creep up. Along with that, the cost of living is going to go up. Health care is going to get more expensive, daily necessities is going to get more expensive. Transportation is going to get more expensive. Meanwhile, wages are going to stay flat or rise at a lower rate…As we globalize, companies will find cheaper and cheaper labor elsewhere. The plight of the middle class isn't too promising moving forward.