For weekenders, I love my GG Mariposa Plus (24oz).
For my 8-dayers, I love my Mountainsmith Auspex (3lbs 11oz).

1. Winter, or 4-7 days other seasons-Circuit
2. 2-4 days GG Gorilla

My Kelty Goshawk 2200ci is only my 2nd pack and i love it. Its not exactly UL at 34 oz, but is way lighter than my old Jansport 5500ci pack that was over 6 pounds. Its big enough for weekends with plenty of compression options, yet light enough to keep my base weight around 9 pounds.

Mine is my six moon designs traveler.

Obviously lightweight. It can be frameless. The best features to me are the comfort while carrying and the space. It is almost too large for the gear that I carry.

-Carries well
-Right size for my gear
-Can reach side pockets easily while wearing
-Back pockets keep things handy/drying

Highly recommended!

Mountainsmith ghost (original blue model) for shorter trips
Mariposa for longer.

I am almost always carrying a bear canister, so need a little more volume.

Right now a 2005 Starlite with stays (28 oz.) but teetering on ordering a 2010 Swift.

For high weight trips (lots of water) the Mountainsmith Auspex is hard to beat, with out top lid 3lbs. 6 oz., haven't carried it in sometime though as I have pushed the Starlite to 40#

Blast 18 is my favorite UL pack

Mine weighs 5.6oz and can carry 22lbs including a Garcia bear canister very comfortably. I fold over a 1/8" thinlight pad to use as padding.

1st gen ULA Conduit, it just works and is so comfortable. My only change would be to have GG-style mesh pocket for a SitLight pad. That said, a GG Gorilla may be in my future.

What ULA packs do that allow them to carry so well (and what I've yet to see from any other manufacturer) is where the shoulder straps attach to the bottom of the pack. Not the bottom-front where the hip belt attaches, but the bottom-back where the big outer mesh pocket stops.

Actually, I just checked and the newer models don't do that anymore, bummer.

But I love my Osprey Exos 46. I have mine down to 34 oz. For those who say it isn't UL, it is when it combined with all your gear is still under 10 lbs base weight.

I didn't like the frameless GG Virga or Golite Jam (2010) or the ply frame Golite litespeed.

The ULA Ohm for all my trips up to 10 days so far, which means a weight of ~ 26#. I have carried up to 32# on training hikes up to 12 miles, so I suspect I could squeeze a couple more days out of it if I had to, but I doubt I'll ever stay out that long anymore. That said, at 32# it starts to sag a bit and the last 6 miles or so get somewhat uncomfortable, but still tolerable.