It’s often wet here in the UK so keeping your camera and accessories dry needs to be considered. I’ve been using Exped Dry Bags for a while now and I think they’re great. I use one for my ThinkTank holster (and contents, of course) another for my Lee filter kit and another for accessories.The Exped’s come in a variety of sizes, are light and have, so far, done their job of keeping stuff dry admirably. They are inexpensive, too. Available from good outdoor shops - I got mine from Joe Brown’s in Llanberis.
A word of warning... THEY’RE NOT SUBMERSIBLE!