These are all good packs.
I own an older GoLite Jam (before it came in different sizes) and it was my preferred pack for a very long time. Despite what some haters say, GoLite makes a reasonable tradeoff between weight and durability in most of their stuff. I would rather that the front pocket were mesh, but others feel exactly the opposite.
I'd add Mountain Laurel Designs to the list- I've had good experiences with all of their gear including packs. My MLD Burn is about perfect for a long weekend- 11 ounces for a pack that size and with those features is outstanding. They also make a reasonable tradeoff between weight and durability, though they do err more towards lightweight. But it's still REASONABLE. Their Prophet or Exodus is the size and price you are looking for. I admit that I'm a bit of an MLD fanboy, though.
A friend of mine has a Gossamer Gear Gorilla, and likes it a lot. GG seems to have had a similar weight/durability philosophy as MLD when they designed this one, though they erred a scant bit heavier. Some of the older GG stuff that was made of thin silnylon was IMO far too fragile in the interests of weight savings, but their current line is reasonable. Or maybe I'm just too rough on my packs, because a LOT of people love their G4s...
I've never even held a ULA pack so I can't help you there.
I own one of the larger Osprey Exos as my "high-volume" pack and I like it a lot. It is essentially a full-featured pack, at a reasonable weight, though significantly heavier than these others we've meantioned since it has a real albeit light frame. I'm a particular fan of the side pocket design, though others hate them. The quick-load trek pole sling is nice, too. I've only used it a handful of times, but it is holding up well.
I've only handled the REI Flash series in the store, but they look reasonable- more in the same category as the Exos than as the cottage packs, though. Like the Exos they are one of the standard "reasonably light but still mainstream" packs that BPLers tend to recommend.
Really, I think that ANY of the packs mentioned thus far will serve you well.