In reply to MartynW:
Another vote for the Talon 22. Had mine 2 1/2 years now and it’s been my go-to sack of choice for three-season use ever since with many days use. (In winter with axe, crampons, more clothes etc, I use a bigger sack)
Capacity just right for me, very comfortable, even when fully loaded (pretty sure in the pic I have a rope and some gear inside, just in case we needed them… we didn’t of course!). Have used with a climbing harness on Skye, little bit of climbing and abseiling etc, though mostly scrambling/walking.
I’ve used it for bike/hiking a fair bit. Like the external pockets, often stow the poles there as in the pic, though they also go inside if I’m worried about them catching on something. Hip strap pockets good for snacks, smaller items.
In fact the only feature I haven’t used is the bike-helmet clip, as if I’m cycling I have it on, and if I’ve left my bike somewhere I usually leave helmet with it!