I was in the same boat recently, that is until I swung into the local Sportsmans Show and tried out the Wilderness Pack Specialties Bighorn pack. I was thinking something along the lines of a Sitka Bivy 30; something in the 3,000+ cubic inch range, that could haul 3-4 days wroth of gear. I was sold on the Bighorn pack due to walking around with the compact frame with 100lbs of sandbags in it. I bought one on the spot. The pack itself offers perfect pocket placement, 3,000 cubic inches of compartments, and plenty of lashing points. Plus, I can get a 1,400 cubic inch add-on later. This pack is my first external, and weighs slightly more than most packs, but that is not an issue, cause 50lbs in the thing feels like 20. Sorry if I sound a bit preachy about my new pack, but it rocks! The pack should be in the $300 range and is 100% American made, gotta love that!
P.S. the reason I stopped to try the pack out was a head-to-head competition between my neighbor (who had a Wilderness Pack Specialties pack) and my Badlands 4500. We hammered 3 miles of nasty terrain, each carrying 60 pounds, and I was amazed at how his pack handled compared to my 4500. Granted, the 4500 has been an outstanding pack in itself!