If you already have a summer-only setup for the good weather then it is a no brainer. Snow tires. You've already decided not to compensate during the good weather so do the same for the bad weather. And remember this - Snow tires are not simply for the snow, they perform much better than all seasons in COLD weather period. That is one of the bigger benefits of running them.
My advice would be to run a high-performance snow tire (I use hankook icebears) that'll provide good traction in cold weather, still performing decent when it is dry out, yet still giving the extra confidence that you'll want when it does snow. I've been to CO a few times, another reason I'd recommend the performance snows is because of how windy many of the roads are out there, you'll want good traction on cold pavement w/ all the curves.
'08 GT sport/premium, tints 20/35, 18" TSW nogaros w/ bridgestone blizzak winter, 19" sport oem w/ hankook evo summer, Philips crystalvision bulbs, debadged, Vararam OTR, JBA 1-3/4" LT's, ported TB, MF axlebacks, MF X-pipe, DBA-powerslot brakes, russel SS lines, hawk ceramic pads, GXP shocks/struts, lovells poly strut mounts, Slowhawk Tuned 344/356
Gone -'04 GTO A4 2.5" custom exhaust, sweet thunder muffs, H pipe, Z06 heads, Baer brake it, 20% tints, torrid red, AEM brute force intake, tuned