As has been mentioned the snow route law is that all commercial and multi-axle vehicle have to carry chains. Depending on conditions CDOT and the state patrol can implement a couple levels of road restrictions. The very most common is that trucks must chain-up. This does not include passenger cars or light trucks most of the time. There are higher levels of closures that can in theory require a car to have actual snow tires, chains, studs, 4x4, etc. But almost without exception they go from commercial chains to road fully closed. FWIW this is usually only interstates and primary roads. Secondary roads in a decent storm it's up to you to be ready, which is why we have chains for our cars.
I have two pairs of chains from tirechain.com. They are a good deal, work fine. I've used the rubber band tensioner and the springs, of the two I like the rubber band better since it does not ice up. I got the medium duty twisted links and they have been a good choice for my little truck.
For her little FWD we have Thule cable chains, the regular ones not the super aggressive ones for ice. These are super easy to put on and have saved our bacon a couple of times. The alternative to these are real snow tires, Blizzaks, etc. We don't have the money for two sets of tires and nowhere to store them, so keeping a set of solid M+S tires on the car and chains if really necessary works fine for us.