I am very familiar with Novato Highlands since I cover that area and I have many friends who live right there.
Depending on your purpose for the question, but if you are thinking about having your property reassessed; I think $750K to $800K is a safe number to use. There are several 4 bedroom homes on and/or around Santa Maria which closed around that time; a couple are smaller and are not nearly as nice as yours, not to mention the amenities you have.
The difficult part is there are a couple of bank owned homes there right now, which was short sale for a while and ended up being REO. This, as you understand, artificially drives the price down.
If you or others need more detailed info and/or comp on this, please do email or call me - Although I would not be surprised if you know the area very well also!
Sylvia Barry, Marin Realtor
Frank Howard Allen Realtors