Even though a Realtor or lender might think you can afford to buy a certain house, you must always consider the ramifications and decide what you really can and want to afford yourself.
Let's say you have an income of $40,000 and my web calculator says you can afford a $120,000 house. What that really means is a lender will give you a loan large enough so that you can purchase that $120,000 house. If you are someone who regularly barely keeps your checking account above the minimum you really will not be able to afford the house. The only way you may be able to keep up with the payments is to throw more and more on your credit cards. And then you will curse me and my silly calculator.
It definitely depends on the housing market in your area. In some places a $200,000 house is a luxury home, in other places that is barely a starter home. People who live in the more affordable areas have the most options. They are the ones who must decide not only "how much can I afford?" but "do I really need all that I can afford?".
Much of this is discussed in the book The Millionaire Next Door by Stanley and Danko. People who live in expensive neighborhoods are not necessarily the ones who own the most assets, just the ones who spend the most money. Their environments give them a model of how much money should be spent. That's just natural due to day to day exposure. And every persons actions affect others in a specific environment. If just one neighbor buys a new Mercedes that is no big deal. But then if after looking at it a while his neighbor decides maybe he needs a new car, so he gets a Lexus. Then another neighbor thinks "well, if they can afford new cars, I don't see why I can't", so she goes out and gets herself a BMW. Soon people who drive home in that neighborhood in a 2 year old Taurus will think there is something wrong with themselves. However several blocks away in a less affluent area that 2 year old Taurus looks pretty darn nice...
You might find yourself perfectly happy in a less expensive neighborhood in a less expensive house. If your housing costs then end up only being 10 to 15% of you earnings, think of all the extra money you will have. Plus the "neighborhood" factor changes. Personally I have found that middle of the road neighborhoods are more friendly and comfortable than more affluent ones. You also want to consider who you want your children to think of as normal peers and a "typical" lifestyle. ("But, Dad, everybody flies to Europe for Spring Break!").