My new favorite is the wingnut Hyper 3.0.
Wingnut uses a floating harness which allows the pack to sit on the hips & not on the shoulders which is much less fatiguing and more comfortable than a camelbak style design. Plus, all the pockets have side zippers & are accessible without removing the pack. And on top of that, it has far more room than a camelbak mule but can be compressed with the attached straps to a very reasonable size so it serves just as well for a quick spin as it does for an all day epic where I'm hauling pads & layers.
The bladder has an ingenous quick release valve so that the hose can be disconnected from the bladder without causing leaks and the bladder comes with blue hot/cold packs built in so it stays cool during summer & warm during winter.
www.wingnutgear.com
Mountain High Cyclery just got their first shipment and most of us locals have already snagged them.