The biggest question is how big a house payment you feel comfortable making each month? Generally speaking, if you have a decent credit, lenders would probably get you qualified to buy just about any house. That goes to show you that if you want a home, Lenders will most likley qualify you for a home!
A couple of things to consider are that the interest on your mortgage is going to be tax deductible and if you finance your home with a fixed rate mortgage, you will be locking your payment in for the duration of that mortgage (taxes and insurance can vary, but your principal and interest portion of the payment will stay the same).
So, how much do you want your payment to be? Subtract out the monthly taxes and insurance and that leaves your principal and interest payment. Add to that number the amount of your down payment (if any) and we have how much home you can afford! Confusing? Call me, we'll help you figure it!