ProTactic 350
Timbuk 2 Messenger w/insert
Lowepro 250 sling for single lens ooutings
The Protactic is a great field bag sturdy wise, it's a bit heavy but where does all that protection come from, right?
I tried the folding top bags and it just wasn't me but I can see how they would appeal, like the WNDRD and such. Another thing that I have realized over the years is all these hook and loop/Velcro based bags and inserts wear out and the main culprit is the soft fuzzy part sewn into the main body of the bag. Some brands gives out and goes flat (no grip) pretty quickly, I like how Lowepro hasn't.
You should check out Top Loaders.