Originally Posted by SirMike1983

For a small, barrel-type bag, I use the Banjo Brothers Minnehaha canvas barrel bag. The Minnehaha has a hard plastic interior liner that is kind of a half-log shape that prevents it from getting too deformed. It's good for an afternoon ride type thing - wallet, keys, cellphone, etc. It won't hold a ton of stuff, but it's enough for me to go riding for a couple hours on a nice day. I have one bike with a Carradice "Zipped Roll" bag, which is a little bigger but similar sort of thing. It's a better bag, but it's also more expensive. I like both.