I just had one. I've been wracking my brain trying to figure out the best way to carry my stuff. I've worn backpacks, mess bag, panniers, strapped backpack to rack... only thing I haven't tried is a big seat bag like Carradice. Or a trunk bag...

Anyway, the little light bulb went off- just use the current backpack for essential items, but put the clothes/layers in a stuff sack and put that on the rack. Distributes the load better, takes a bunch of bulk out of the backpack, leaves room in the pack for any items to be picked up on the way home...

What was your 'A-Ha!' moment?