[pct-l] Best Backpack for multi-day trips

[James]

My Northface backpack is a little dated and I would like to upgrade it with the following enhancements:

More outer pockets
Zip out center of pack to get to everything more easily
Compressibility when used for summit pack
Better fit on my back with some ventilation as well
Section designed for Bladder Hydration Systems (that can be used for other things as well)
Expandability for carrying larger loads (i.e. Sleeping Bag, Bear Cannister, & Tent)
Lighter Weight (current pack weighs over 5 pounds)
Shovel, & Probe Pockets
Straps or other system designed for carrying skis
Convenient system for attaching poles
Convenient system for attaching ice ax / crampons

Even if your pack doesn't meet all of these specifications I would greatly appreciate feedback from those of you who spend a lot of time on the PCT and know what works for you.  My main interest is multiday trips to summit.  I am planning multi day trips in California (Mt. Tyndale via Shepard Pass - Did Williamson last summer), Nevada (Ruby Dome) and my home state of Colorado (day trips to Mt. Sneffels, Shavano, Tabegauche, Harvard, Evans & Longs Peak).