I currently live 15 mins east of Boulder, and it's pretty ideal. There's some snow in the winter, but also plenty of sunny days in the 60s, and I like getting the chance to change it up and xc ski for a few months. Denver is a huge metro area close by. The riding is amazing, bike culture is completely pervasive. The climbing is out of this world awesome. Can't say enough about it. If you live in Denver or Boulder, there are plenty of people who don't even own cars. Boulder itself is pricey, but 15 minutes out of it is much more affordable. Denver's pretty reasonable depending which neighorhood you pick, schools, etc. I find it's a lot easier to ride from my house here in Lafayette than when we lived in Denver. There, I usually ended up driving a little bit to ride.
Moved here from Tucson, where the riding was awesome, and true year-round riding was the case, so long as you didn't mind getting up early in the summer. Seriously, tho, there is no riding season. It just goes and goes and goes. The roads outside the city limits are mostly all new, and they all have great big bike lanes. It is *not* a city that you can get by in without a car, tho. Tucson is extremely affordable to rent or buy, tho it can be harder to find a job that pays well.
Before that, I lived in the the South Bay and a little ways up the peninsula in Menlo Park. I still go back there for work once a month. Also great year-round riding. It never gets too hot to ride, and is rarely too wet or cold in the winter. It is super super expensive. Unless you can do something that's valuable to the tech industry, it can be really hard to make ends meet here.