The amount you choose to finance is a personal choice. Each state has different homestead laws. You may not be able to borrow against your property later for things such as a college education. It's a good idea to read more about these laws before you make a down payment decision.

As a general rule of thumb, you should not exceed 28 to 29 percent of your gross income for your total house payment, and 36 to 41 percent of your gross income for all your fixed monthly obligations, including house payments.

The most important factor is your own comfort level. The best thing is to contact your lender and ask for an estimate several ways.