It depends on several things....mostly size and finishings. I've seen homes built (excluding the lot) for $80/ft and I'm working with a friend of mine that is building in Memorial for $250/ft. The average for a very nice home runs between $100 and $120/ft. The location and cost of the lot are a huge variable. Lots range from $16,500 in the suburban market to over $1,000,000 in Memorial and closer in.
Best of luck to you!