Talon 33 is a good choice, I think. Another might be the Atmos 35:
http://www.bikepacking.net/reviews/packs/osprey-atmos-2535/I have the Atmos 25 (I don't think that one is made anymore) and it worked well on a few ~3 day backpack trips. It was a little low on capacity, but I was able to strap my pad and sleeping bag to the sides using the straps. I liked having the internal frame on the Atmos for support when hiking, that's why I mentioned it as an alternative to the Talon. Atmos is not bad for riding, but I find the Talon more comfortable.