mornin' Swordy!!!
>How much house should one be able to afford
IMHO it is best to NOT buy at the top of your lender's recommended range. It may lead to many mac and cheese dinners.
Buy in the best neighborhood and try to be the smallest house on your street. When you go to sell, the comps will be favorable.
Find a good mortgage calculator online and determine how much of your NET income you're willing to do without each month.