Thanks everyone for the help! I checked out the Detuter at REI. I really liked it. I'm going to go back and get it this weekend. I like the suspended back and the mesh straps. I feel like this bag is going to help a lot!

I understand nothing is going to keep me 100% dry... but if i can get 50%+ more dry I'd be happy! I tried on some Ospreys at performance and they felt like they wouldn't help much. It had a mesh on the back but it was right against your back and I felt wouldn't reduce sweat.

On the Detuter, I really liked the trampoline-like backing that helps keep most of the contents off your back!