I haven't done any rides longer than three hours yet, and for that I'll have spare tube+co2-inflator+card/cash+cellphone in my seatpost bag, plus a little room left over to stuff my windbreaker in. (Yes, I still have a big dorky seatpost bag).

But I'm just finding out that having an energy bar thingy or two in my jersey pocket IS handier than having to rummage it out of the bag and having spare tube+co2-inflator etc. start falling out...

Off to buy arm warmers and tights/leg warmers today! whee, new sport to shop for!