When coupled with current outstanding loans, the total for your debt service should not exceed 40% of your gross monthly income. Some lenders may have slightly more liberal requirements or loan interest rates which may increase your purchasing power.
Mortgage interest, property taxes, loan fees or "points" are currently tax deductible (up to allowable limits). Points are generally deductible in the year paid. A point equals 1% of the mortgage amount. If you are in the 32% tax bracket, this is equivalent to receiving a 32% discount on your mortgage interest and property taxes. During the first years of the mortgage your tax savings are especially high because most of your monthly payment goes toward loan interest.