My wife and I live in Sonoma County (in fact, we were both born and raised here). It is a beautiful place to live, and we intend to stay. Because of its proximity to the SF Bay area, it has become very expensive, however, it is also an area that has been hit hard by the housing bubble. Home prices are down about 25% from the peak in 2006, and there are bargains to be found (as if ANYTHING in California can be termed a bargain). For example, there's a house on our block that is currently listed at $400K, but was last sold in 2005-2006 for $530K. Apparently, the previous owners took out one of those variable interest-only loans that imploded on them. These same homes were going for about $300K in 2001.
Sonoma and Petaluma are relatively expensive and except for Healdsburg, the Northern part of the county tends to be the least expensive. Windsor and Cloverdale still have some moderately priced homes being built.
Weather here is great compared to a lot of the US. Winter highs range in the 40°F to 60°F range with 30" to 50" of rain, depending on location. Summer temperatures run in the 75°F to 95°F with an occasional hot spell in the 100s. We can get some rain well into spring; fall is usually spectacular, with warm days and cooler evenings than summer.
On weekends and during off-commute hours, it's about an hour drive to the Golden Gate Bridge, and just a bit longer into SF. It's less than an hour to the Sonoma coast, where there is spectacular scenery and numerous beaches. The ocean temperature here stays in the mid 50s, so it's too cold to swim in for extended periods without a wetsuit. There are also several lakes (Sonoma, Mendocino, Berryessa, etc.) in the area for boating. And, as has been noted, there are hundreds of miles of country roads for bicycling.
And of course, there are also hundreds of wineries and many great restaurants in the area. It's truly a great place to live, but definitely not inexpensive.
