OMM Jirishanca
I have one of the older models (2nd gen, I think... the 3rd gen are just coming out now) bought second hand from another OM-er a little while back. They rushed in and out of favour on here for some reason. I got mine reasonably priced as a result.
It is just roomy enough for a kit-heavy ski tour... inside I could fit my skins, couteaux, crampons in a bag (some relatively chunky old Black Diamond things, maybe an old pre-stainless Serac?) avalanche probe, down jacket, microfleece, and water bladder. For a hut-based overnighter I coudl squeeze in a change of socks and undies, a sleeping bag liner and toothbrush, too. The MSC held down a collapsible shovel nicely, an ice axe fitted on the outside and the hip belt pockets held a bag of trail mix and a few cereal bars. When reasonably full, it does a good job of holding skis in an a-frame carry, and fits my relatively wide 92mm waist touring skis fine. When not so full, it tends to be a bit flopping for a good ski carry, but you can tighten up the MSC enough to keep things under control.
I'd have liked a tiny bit of extra space (I couldn't take my boot crampons and my dSLR at the same time, for example), so perhaps next time I'd consider a 40+l bag. Possibly the new OMM Winter MSC would have enough space in it to do the job. I'd have taken my Trio chest pouch only a) I couldn't find where I'd hidden it and b) it would have made taking the rucksack off for use on chairlifts (which we did a few times) a bit of a faff.
Zero durability issues, and no problem with waterproofness either: wiping out hard in soft snow means you get that stuff everywhere, and though it all melted off the inside stayed nicely dry.
Edited: 12/03/2012 at 12:05