The vector series ospreys are nice. Mine is long in the tooth but still gets used. My wife almost picked up another for $40 at a thrift store but wasn't sure if it would fit me. I run the silhouette with the vector compression but no lid. It's about 6lb in that config and around 6000 cubic if I recall.
You can do a lot worse than a Kelty cache hauler for heavy loads as well. The compression buckle broke on one load out but that's really my only complaint for what it is. For big loads it is what I would go to first.
