Lots of variables there. Construction is usually estimated in terms of price per square feet, and property values can represent a substantial fraction of the total price of the house. A 'modest', 'old' house in a good location can be vastly more expensive than a 'McMansion' built out in the suburbs or something. Also McMansions are usually built where land is cheaper, so more space.
For families with children, there is also the cost of education to consider. There are scenarios where avoiding the need to use a private school to educate your children can completely pay the cost of a home in the suburbs. (Even considering property taxes). The house can effectively burn to the ground when you're done educating your kids and you'd wind up net money ahead compared to where you might have been with a more modest house and private schooling.
But a McMansion will almost always cost you more than a more 'modest' house offering the same amount of space. Also that house will almost certainly be better constructed.