I wasn't a huge fan of living in Napa myself...and there is really not that much to do. Yes, there are plenty of outdoors opportunities, and it has a fine farmer's market and lots of local foodie stuff (really that's its strength). Lots of overpriced restaurants that take themselves too seriously...
As for neighborhoods, well it depends on what kind of housing you like. Near downtown there are lots of older houses with interesting architecture, while on the edges of town its just basic neighborhoods. There is more crime in some places less in others, but its mostly property crime. check out this link:
Napa crime map, May 2009 | Napa Valley Register
I like the town of Sonoma better myself.