Originally Posted by
Bean Counter
The best option for taking clothing to work, including shoes is a saddle bag.
Carradice have a range of sizes up to a sort of expandable Camper long-flap 24L ish (the one I use for work and for the odd multiday euro touring). Not cheap but excellent, some have leather straps like the camper but others have rucksacks type clips.
Carradice also has a quick release/support that fits on the bag and seat tube so very easy to fit/remove bag. Due to fitting to the seat tube should fit 99.99% of bikes. Also means that the weight is carried where the bike is designed to carry weight.