In reply to exiled_northerner:
I'm in a similar position. My 20yr old Macpac Tuatara is due for replacement.
But, I've always had a soft spot for Lowe Alpine packs, having had an Alpamayo 70l sack in the 90's and now a Cerro Torre as my large sack. Both have been totally indestructible.
For a year, i've been using a Mountain Attack 45:55 for bivi-trips, and i'm thoroughly impressed by its relatively low weight, comfort, durability and features but its perhaps a bit large for single day out so i'm looking at the Peak Attack 32 to replace the Tuatara.
You could perhaps consider the Crux AK range, i think they are closest in design and philosophy to the original Pete O'Donnell packs.