Edinburgh Bicycle Co-op's range of Stow rucksacks have been around for a few years now and are much loved by the two wheeled community. This Stow Expert is the biggest of the family, with a capacity of 25 litres and an extra 5 litres available at the tug of a zip. It shares the excellent Aeroflex frame system with its little brothers and that guarantees a less sweaty back than your bog standard backpack, plus you don't get poked in the back by awkward loads.
Carradice have been around for a long time, are beloved by bearded men on antique steel tourers and I have been warned that saying anything disparaging about this Super C would result in me being pursued to the ends of the earth by gnarly CTC types. That is to say, slowly and with frequent breaks for tea and cake.
Happily I came to love this bag, but it took a while...
The Boblbee Megalopolis is, I grant you, not a very catchy name for a backpack. It’s not primarily intended for cyclists, but this piece of kit is safety accredited as TUV/CE as a back protection device and it can provide a valuable service to road riders, especially those of us that do battle with the traffic or need extra back protection.
Ortlieb's TIZIP closure is the standard setter in waterproofing, and you could chuck this messenger bag in the river and still have dry clothes for work. There's ports for adding such extras as a sternum strap (one is supplied and you'll need it, as the bag is slippery) and inside there's, well, space for stuff.