Hey Thanks......^^^
To answer your question, You could go with either a snow tire or an all season tire. Here's what what I would do.....(and what I am doing for that matter)
Since your in CO, I would recommend getting a set of dedicated snow tires. Steel wheels for 1st gen xB's are a dime a dozen and since you don't have TPMS sensors in your wheels, switching from summer tires to winter tires would be a breeze. Get a nice set of tires for spring, summer, and autumn and when you feel that snow is coming, get the snow tires bolted up and leave them till spring.
The nice thing about switching tires/wheels like that is your snow tires will easily last you a number of seasons. You'll stretch the life of your 3 season tires as well since they wont be used 4 or so months per year.