ZERO! There is only one loan that I know of that offers such great flexibility and incentive...a VA loan. If you're a Veteran (and thank you for your service) a VA loan is a valuable tool in the home buying process! I just had a client use the product through Kevin Gannon at Wells Fargo, and I was so delighted for the client!
It completely depends on your personal financial situation. There are so many different types of loans...traditional, VA, FHA, MassHousing, etc. There are grants out there for buyers in certain market places, and heck, there are even hard lenders or private financing that can be obtained for the right buyer.