Honestly? For the features you want it's a little larger but hits virtually all the buttons: Osprey Aether 60. I have the 85 which is overkill until winter camping (but for $100 when it was new enough to have the tags put back on it I'm not complaining!) and am looking at the 60 for summer hikes.

It has the second entry, detachable top, etc. I can also say that an overloaded 85 still can feel like you are virtually wearing nothing even on a nice 2,500' ascent over 1.5 miles. smile (I noticed my legs being out of shape, not the 45lbs on my back!)