I've lived in TO for about 10 years -- here's my take on it:
Beautiful open spaces, adjacent to hiking (Santa Monica Mountains and others) and the beach about 30 minutes away. I think the weather is just about perfect, not too many overly hot weeks and for most of the summer it cools off nicely late afternoon-early evening.
Very family oriented, kid friendly place overall. Be forewarned, the school board just voted to close two elementary schools (Meadows and University I think) so if you have kids that age, check into how far they'll have to go for school. I'm pretty bitter about it actually, even though I don't have kids. The school board seemingly gave the big middle finger to parents and homeowners, crying poor but oddly never even offering homeowners a chance to vote on parcel tax. Well take that however you like, but personally I see it as a bad portent for the City. Just my opinion of course, but you can Google and read up on it if you like.
If you are looking for nightlife, overall, forget it. There are some nice restaurants/lounges but pretty much the City is quiet at night. At 6 pm driving down TO Blvd you're in traffic. Same street at 9 on a weeknight, and it's pretty much empty. It's a little livelier than it used to be but still I think it would be thought of as pretty much "rolling up the streets" at about 9 pm on weekdays. Well I like that personally but I know some don't.
I agree that people here are friendly. It is a very different feel than 20 minutes down the 101 into Calabasas and the San Fernando Valley, which has a more Los Angeles feel.
Personally, I think growth is getting a little out of hand -- I heard about "build out" several years ago but still they keep on building, which seems to me a bad plan when housing prices are dipping pretty badly. Well maybe everyone complains about too much growth where they live, I don't know, and it would of course depend on what you are comparing it to on how you felt about the growth/building factor.
Plenty of shopping, lots of churches and family activities and so much open space nearby do make Thousand Oaks a great place to live. Just pay attention to the "newer" things being built or having recently been built to get an idea of what might be changing in TO. The City has been very suburban almost to the point of a sort of light rural but recently there has been talk about "mixed use" and that type of thing, which has been pretty much unheard of in the area. They're redoing The Oaks mall, which is a good thing as what we had in no way was keeping up with the progress of the City. They are putting in Nordstrom and down the road I think a Neiman Marcus and the mall will be both indoor and outdoor.
If you find a house with oak trees on the property, make sure you ask your realtor to explain the oak tree laws.
Oh, one poster said there was no "bad side of the tracks" in TO -- I hate to disagree, but yes there is. I think there is a bad part of almost any city unless it is pretty small. There are at least a couple of not so great neighborhoods I can think of, including some gang activity, although probably not more than any other So Cal city of this size. Overall the feeling in Thousand Oaks is one of safety -- you feel you can ride, walk or jog the streets without feeling threatened, in pretty much all of the City.
Housing prices are high and as it seems likely there will be at least another year of dip in prices, it might be wise as another poster said to rent for awhile rather than buy.