Super large but lightweight - Rab Expedition Kitbag 120

This duffle is perfect for a week long or more trip. It's bigger than it looks online and will hold everything you need without weighing you down. The exterior is a strong water resistant material. I haven't used it in the rain yet, but it appears water will drain off nicely. It is not waterproof though, just water resistant. Straps are heavy duty and should last many years. I highly recommend this bag.