For a XC tire, the fast track is pretty good in terms of grip. I used a set of 2.0s in a pinch last winter for a agressive trail ride, and they did just fine on rooty decents and rocky drop offs. They did, however, suck in the clay-like mud (but most tires do). You may just want to find a fatter casing.
The specialized resolutions roll fast too, and have very very good grip for all around riding.
I'm sort of partial to spez tires though, since that's all I've been riding for the past 2 years or so.