My Millet Expedition 65 has yet to let me down. I've used it on week+ trips, ski mountaineering, day climbs, and more.

Light - 1560g, but not ridiculously light, so it's still durable
Highly adjustable - volume can be adjusted from ~30L to over 65L (w/ compression straps and an extendable skirt)
Water resistant (proof?) - materials readily repel water, a pack cover is not needed on most trips (unless major storms are forecast, then I bring it)
Extras - Secure ice ax attachments, gear loop on waistbelt, vertical zipper on main compartment for easy access, can easily carry skis (a-frame)

All in all, a one quiver pack in my book.

Osprey Exposure has been the best bag I have owned

My bad boy:



After getting the shoulder straps beefed up gratis via TNF, this guy has been nothing but a pleasure to bring along all of my trips.

Material: 210D Cordura Dyneema, 840D Jr. ballistics, 420 HT nylon
Volume: [M] 4000cu in (65L); [L] 4300cu in (70L)
Suspension: E-VAP Shoulder straps and back panel, removable internal aluminum stays
Weight: [M] 3lb 9oz (1615g);
Recommended Use: Alpine climbing, fast and light backpacking, fastpacking, extended backpacking
Manufacturer's Warranty: Lifetime

The support frame/suspension is incredible!