In reply to Nath:
I have an X-POD. It's very well made, and I like the simplicity. The material is thick which makes it tough, but also fairly heavy. You can save some weight by removing the waistbelt and lid - handy if you are carrying kit in then walking from a basecamp. The back frame is simple but comfortable, make sure you buy the correct size as it's not very adjustable. It is absolutely massive, well over the 60L you mention, probably nearer 100L. I bought it partly for trips I was doing with a student club, where we typically only walked in a few hundred meters to a hut. I also use it for weekend trips, but it's a bit big really. It's nice to have space to pack loosely and rummage around (especially in the tight confines of a tent in the rain) but it's heavier than it needs to be. Even carrying a fair part of two people's kit it will be a bit big.
In short, it's a very good bag, but it is absolutely huge.