I see you have already made a decision but I wanted to mention another option in case others are referring to this discussion. As a resident of Michigan's Upper Peninsula, I have used "Yaktrax" and been satisfied with them. They also worked well on the icy trails in the Grand Canyon on a couple of winter trips there. Last trip in Jan. '08, I met someone using the microspikes. I was impressed with what they were, but they were way overkill for the icy trails we were on. The Yaktrax are a little lighter weight. I would get the "pro" version" -- which means it has a velcro strap that goes across the top of the foot and secures them more effectivelly.

Just another suggestion FWIW.
http://www.yaktrax.com/ProductsPro.aspx