[Alan]

I'm going to agree with Paul. Function before fashion - and from I've heard, I think Uggs are mostly fashion.

That said, a great deal depends on where you are going. In the interior, waterproof is not a necessity, but lots of insulation is. On the coast in the summer, it is the opposite. That said, you will still want some insulation. Ask your tour company.

As for the tread - you'll want some, but it isn't terribly important. Pretty much all treads will slip on ice - or, alternately, you won't want to wear it inside. Yak-trax (a commercial product) are popular for use on ice and firn.

A Canadian company called Baffin reportedly makes some good warm boots, but those are much more than you are liable to need.