are you asking what would be more profitable between selling the lot as is or building a house and then selling it? cause if so i would recomend not building on it... lots of people are looking for vacant lots so that they can build the house they want, with materials they choose and the size they prefer. If you built a house you will have to find a customer that has the same taste as you and that could be harder.
The extra profit you would get from the house woulnd't be worth it IMO.