For the money the ILBE pack it's hard to beat. Complete packs can be found pretty cheap on ebay these days.
I picked one up a few years ago to play around with. I made a few modifications to suit my needs.
First I cut most of the MOLLE webbing off, this got the pack down to 6.5 lbs.
Second I swapped the original waist belt out for a used kifaru one. I have skinny hips and no butt, the original belt never fit me comfortably with any weight in the bag.
It's a little big for day hunts imho but cinches down fairly thin. I wanted to get some field time with it so I used it on my brothers elk hunt last week. It worked out great and hauled quarters out like a champ. I think I may use this one more often.
I've used a gen4 MOLLE frame and pad set the last 2 deer seasons. I cut the suspension off another pack I didn't care for and mounted it to the frame. I've packed out 2 coues bucks with this setup by cinching the meat between the bag and frame. The meat, head, antlers and gear weighed about 70lbs. The pack feels pretty comfortable at that weight, at least as comfy as 70lbs can feel. I wish the shoulder straps were less wide though. This pack also comes in around 6.5 lbs.
My final surplus pack is the Mystery Ranch SATL I got off ebay. It's my favorite of the bunch but it's brown and I'm scared to use it during rifle hunts so it's my archery bag. It weighs in at 4.5lbs, I added a little extra padding to the lumbar pad, ordered padded belt pieces from MR and swapped out the flimsy fiberglass stays with pieces of carbon arrow and got rid of the rolled foam body armor support things.
This pack is super comfy and light. I've only packed out a javelina with it, probably a 45-50lb load but it felt good. This would be my go to pack most of the time if it wasn't brown.