Boulder. You can ride year round but will want to avoid mountain roads with gravel in the winter. I didn't miss any work when I only rode two wheeled vehicles, and only had a few days when I was riding cyclocross tires dressed like I was snowboarding.

The Boulder Creek Path will get you from west to east side without traffic lights so it's easy to get to mountain and plains rides.

It even has a mountain within city limits.

Settle for less luxurious accommodations than you'd have elsewhere, like a townhome instead of a house.

I lived in Boulder from 1991-2006, and only left because there are more interesting software jobs elsewhere.

California is nice too. Where I'm at in Silicon Valley the cycling varies - while the weather is great year round, viable rides before work are flat and require riding through a lot of traffic to get an uninterrupted stretch of road. The mountains are nice, but climbs shorter and less scenic than Colorado. Home prices are staggering - if you want a house near a walkable down-town you can add a million to what you'd pay in Boulder which is allegedly expensive.