Although I don't know for certain, the resale value based on number of rooms would be more based on customer need, not size of house.
Here are important things to keep in mind when selecting a house:
1. Storage areas. The majority of Houses built today don't put enough storage areas in a House thinking they can upsell you with add on work. If you are like me and my wife and don't think about stuff like that when you are young then you end up with a House without enough storage space.
2. Neighborhood "friendliness" - What I mean by this is will you be happy with the Neighborhood. It's easy to fall in love with a House, but if the House surroundings don't meet your lifestyle that love is going to turn into resentment sooner or later. Things to avoid: don't live on a busy street if you have children or are planning on having children(mostly talking toddler-teen age here). The best thing to do is before buying a House, go spend some car time in the neighborhood on a typical Saturday morning/afternoon and even evening to get a feel for the neighbors habbits. If you have children you will look for other children around the same age playing.... if the parents of those kids trust their children to play in the neighborhood more often than not you will too. If you want a more quiet existence you will look for that instead.... Hopefully you get my drift.
3. ALWAYS, ALWAYS, ALWAYS spend the money to get a Structural Engineer to check out a house.... whether newly built or an older home. Otherwise you really don't know what you are getting yourself into. Foundation issues suck. Did I mention always do this?
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