I'm loving the 11-liter Zimbale saddle bag I have on my Peugeot. I use the bag with a ViVa saddle bag support, a small rack that attaches to the seat post and is designed specifically to support a largish saddle bag. If I get around to it, I'll post a more extensive review of the Zimbale bag and the ViVa support as a system, but for now, I'll just say that I absolutely love it and very much recommend it as a means to carry small loads around town or on longer day trips.
I especially like the extendable flap on the saddle bag, which allows for larger or bulkier loads in the main compartment and/or carrying bulky objects under the flap. That's a rolled up messenger bag under the flap in this photo, which I was going to use to carry home a small bag of cat food, but it turned out my saddle bag was large enough for both the cat food and the rolled up messenger bag, which was good, because I don't like carrying loads on my back when I ride.
PS. I was not compensated to say nice things about these products, I just like them.