disclaimer: I do not represent or work for Osprey, however if you do or know someone who does, feel free to hook me up, I will continue to advertise for free
I bought an Osprey pack this summer for hiking, and it will be the first place I look for a new winter pack. Last year I used a cheap ($25) Sims hydro pack, it sucked but served me fine (no board carry) inside resorts (I like to hike for stashes in-bounds and having water is nice).
Seriously tho I can't say enough about Osprey as a pack brand. Everything on it has a lifetime gaurantee. It has so many thoughtful compartments and options, everything really...goggle pouch..helmet hook...ski/hiking pole stow...3liter hydro...
After a quick glance it looks like the Kode or Karve (smaller) series would serve you well.
Vertical Endeavors / Snowplay - Osprey Packs, Inc :2011: Official Site
One of the things that was most noticeable between my cheapo pack and the Osprey was the design of the hydration system. For one my Sims pack just froze when it was cold enough and then I was lugging around an ice hose. These winter Osprey packs keep the hose INSIDE an insulated compartment. Another thing I realy noticed with my cheap pack was that the water reservoir was just like a floppy balloon, you could feel it on your back. The Osprey reservoirs have a pseudo-frame built into them so that regardless of how much water is in them, they sit tight in the pack and you can't feel it at all.
They may be a bit expensive, I am far from wealthy but products like this that I know will see use, I splurge. My summer pack was about $120 (Manta 30). You get what you pay for, its nice to know that I never have to buy another one.
I would much sooner buy 1 $150 Osprey with proper outdoors craftsmanship and company backing then buying some "cool" brand like burton, dakine, sims, etc., that will probably fall apart on you the second you have reached the crux of your BC climb.
FWIW ended up doing ALOT of climbing this summer and saw ALOT of Osprey packs out there from multi-day packs to day-runners. People who know, know.