In reply to bigblue22:
I swear by the Crux 'sacks; simple, no nonsense and tough as old boots!
Needle sports stock them if you want to try one on else you can get them direct from Crux!
The AK-37 is great for cragging, although a tad small if you want to take all your gear plus the kitchen sink to the crag. On the other hand it's great for high mountain crags if you split the gear with your partner.
I use the 47 for wild camps and can fit enough in for 3 nights if taking boil in the bag meals! They're both equally comfortable when climbing although the the smaller one is a more favourable size I'd say.
They're properly waterproof and have kept my cameras dry when out in some right hoolies!
Just my opinion, but hopefully of some use!