He is somewhat averse to trash bags as they are not long-lasting enough to justify them going to waste afterwards. He also has an array of drybags from kayaking. He has variouos other pannier sets, including the type Paul Woloshanksy has/had from Army disposal.

I find dry bags much better, also. They are durable and you can squash stuff down and keep the air from re-entering and "reinflating" the bag to bulkier proportions. I believe that bulk, rather than weight, becomes a cyclist's prime consideration when packing.