I haven't used enough packs to have a experience-backed favorite, but if I had the MYOG skills, I'd reverse engineer my GG Gorilla and make it out of 1.5oz cuben.
The 2800ci capacity covers me for everything but the dead of winter, and while 99.9% of the time now I can go frameless(and often hip belt-less) I'm happy to sacrifice the small amount of weight to have a removeable aluminum frame.
I love the hip belt fit, I like the Y-strap on top for securing my bear cannister when necessary(or snowshoes in the winter). Unlike a lot of people, I don't find the shoulders straps to be too wide. I like the external pad pocket. I find the side pockets easily accessible and well-sized.
If the 200D fabric out of which the entire body of the Gorilla is made weighs 4oz/sq yd, replacing it with 1.5oz cuben would cut the the 18.66oz weight of my Gorilla (pack body and hipbelt only) down to maybe 8 oz. Add in the hip belt pocket, shoulder and hip belt padding, sternum strap and some shock cord for compression (~2.5oz all together) and I have a 10.5oz frameless pack. Add the 3.39oz aluminum frame(I much prefer the single piece Gorilla frame to the separate stays of my SMD Starlite) and I've got a 3.5 season framed pack for under a pound.
Add maybe 400-500ci capacity to the body, (and a good compression system for smaller loads) and I could probably use the Gorilla year-round, since my winter trips will almost always be overnighters(never more than two nights) and the frame would provide comfort for heavier loads.