I agree 100% with OMOTM and Kev, the most important thing you can take into the back country is "Common Sense". Get educated on avalances. I've taken 3 of Doug Fessler's courses and review the info. every year. Take any course that's available to you. Most, but not all the time, Mother Nature will give you the warnings. You just have to know how to reconize and read them. I've been riding the mountains for 24 yrs. and even with the experience I've gained, I've been caught in 3 (one just last year) avalances. Fortunately I was able to run out of the path of 2 and out ran the other. I was just plain lucky not skilled.
The next most important thing is equip. A becon, shovel and probe are a must. I won't ride with anyone who's not carrying. I can't understand how people will go buy a $7000 sled, $1,500 trailer and $500 worth of riding gear but not spend another $500 on equip. that could save their life! I also carry rope and tackle (crevasse rescue) first aid kit, signal device, energy bars and space blanket. This all packs nicely into my backpack.
But don't let all the horror stories scare you. The mountain back country is beautiful and thrilling. (I hate flatlands!!) Just get the training, buy the equip. and use common sense!