Studs, boots and keepin' it even (& upright!)
Great advice in the previous responses about traction differential in the various "icy" surfaces you might encounter. I've found that by keeping your weight as centered as possible between the ends will allow you to vary the traction as necessary depending on conditions. Also...don't make the mistake of stopping pedalling and sitting through the dicy stretch, even though it's the natural reaction. You'll end up with your center of gravity waaaay to high and will more than likely be tense, a horrible combo on ice. Keep a gear that you can spin through it and focus on placing weight on the pedals, lowering that old CG.
Booties are a good option and one I've used for years. They have their drawbacks, snow/mud packing, being torn up when walking and such, but better than cold toes. Smartwool socks are one of the best investements for cold, snowy days (or any wool sock!). I've been running the Lake MX series of winter shoe/boot for a few years now and they absolutely transform winter riding. I believe there might still be a few of the older MX300's to be had online (MX301's have new closure mechanism). My toes have been happy on multi-hour, single digit forays but it's truly the "just near freezing" days that they save your bacon, the slush covers them but doesn't get inside.
Studded tires. A good set of knobbies will do very well on the snow but if your route/trails are very icy, then studs are a good investment. Nokians are my absolute favorite and I'm on my 4th set (26&29). Absolutely stunning traction, you'll ride across things that you wouldn't even be able to stand on safely. For a great education on several types available, visit
www.peterwhitecycles.com He carries both Nokian and Schwalbe (Schwalbe now has carbide studs). I can't speak highly enough about the studded tires if you ride mixed terrain and conditions. 99% of your ride might be do-able on a knobbie but once you hit a slick spot and go down hard, the original purchase price won't even be a bother. We ride to several trails here in Colorado Springs and it's truly the time before and after the actual "snow riding" that is the most dangerous! Additionally, due to their heavy weight construction and limited seasonal use, you'll probably get many years out of a set.
Any way you end up doing it...enjoy your time in the snow & ice. It's a season that most spend indoors dreamnig about riding and wishing they had your guts and determination. I love riding the trails during a nice snow storm, especially at night...I feel like I'm getting away with something so fun, it should be illegal!
Oh, the only "real" studded alternative for the 29'er set is the Nokian W240. It's mighty narrow (700X40) but has a full compliment of 240 studs nicely arrayed across it's surface. If you subscribe to the "narrow tires are best for snow" then it's the cats meow but obviously if the conditions allow for a bit of float, you'll be at a disadvantage. However, for icy & rutted trails, the studs from center to edge will give you mucho bite. Hopefully by next year they will come out with a proper sized aggresively studded tire/s for the Big Revolution!