Being that Granite Bay is a relatively solid market with highly rated schools, strong per capita income and all the amenities that a resident would expect in a luxury community, I would say that Granite Bay should stay fairly healthy when compared to other newer areas. The one thing that makes Granite Bay a less sought after area could be the entry level pricing and distance to downtown Sacramento.

Most areas are seeing a sharp decline in prices and that includes Granite Bay. Expect the prices to continue to decline this year and with any luck it will start to stabilize in the next couple of years.
Don't expect appreciate for a while, the dust needs to settle down after the market stabilizes.
Hope this helps,
Ken