OK bringing back an oldie: And pack weight be damned! My back hurts with 10lbs- I don't care if it added 12oz!
So I have a Zimmerbuilt pack and love it but hiking Glacier this year with 27lbs for 5 days I discovered that the hipbelt wasn't enough for me. (lil bitty 'wings' and webbing only) It cut into me a bit and the bottom of the frame dug into me on both sides. It made me bleed a bit even. sucked… My back is a POS so I have to put the vast majority of the weight on my hips.
When I got home I Googled REIs replacement hipbelts, mostly cause I know they sell a few different ones. I ended up getting this one:
http://www.rei.com/product/766120/gregory-3d-hipbelt (PS: I cut the worst-in-the-indusrty pockets off it)
It fits my sexy bod perfectly and slips right over the existing belt. I've used it a few times and I have to say that this is definitely the most comfortable I've ever carried a pack.
So to answer my old thread's ponderance, at least for me, Yes- the hipbelt is very valuable.
In fact, I used to put a lot of value in the lumbar pad, which my current system does NOT have at all. its just those beefy hipbelts, hanging on my iliac crests. For me this is invaluable, as I usually fiddle with my pack the entire hike, and have't really been comfortable, just dealing with it.
If anybody gives a poo I can post some pics of my mutt pack… Zimmerbuilt (non custom/ clearance bin) pack, Ohm hipbelt pockets, Gregory hipbelt