If you are on a budget and/or haven't been sold on Ortleibs, I would recommend Seattle Sports products. I have only used them for two weeks of a tour on the Natchez Trace and it only rained once, but they worked well. They have a dry bag type closure on top and I like the attachment hardware. I use dry bags, zip locs and nylon stuff sacks to keep things organized. I think they are a good bit lighter than the pvc coated Ortleibs. I also use an Avenir rack trunk bag that is only water resistant, but it was much less expensive than other brands, is well constructed, and I only put things in it that can survive being damp.