So far I'm considering the Osprey Argon 110 or the Web Tex PLCE. Capacities are 110 litre and 120 litre respectively. I like the look of the Web Tex pack better but they're straight out of the UK and I can't find any reviews of their products as of yet. So far, everything I've read about the Osprey tells me it'll have more than enough volume/features and it seems to have a pretty good rep as a reliable pack.