Originally Posted by DnA362
Camelbak HAWG.
The Mule has some packing space, but you loose all the real cargo capacity when you fill the bladder. The Mule is really only appropriate for holding a frame pump and a handful of small items.
The HAWG will cinch down to about the size of the mule. But it holds WAY, WAY more. If you're planning the occasional day trip, the HAWG is your best bet in the Camelbak line. You should still be able to find '04s for cheap, probably even in the UK. I'd stay away from the '05s because last year Camelbak seems to have had a "queer eye" year in '05 where they made all their packs look like they were marketing to little girls. The '06 models however are VERY cool. They've gotten a little "squarish" and tough looking. They all look a little more like military packs now.
There are some other lines out there, notably Oakley. And Oakley is good because they do NOT make bladders, they just sell you the pack. Nobody out there does bladders and valves as well as Camelback.
There are some systems out there that are designed to ride VERY low on your back in order to lower your center of gravity. These are worth a look, but just remember that a normal pack tends to sag low anyway. Once the bladder is half empty, it will all be the same.