I'm disappointed that no one's said Geigerrig so far. I first heard about it from /out/
Reversible (for easy peasy cleaning), pressurized bladders for cleaning, sharing, irrigating wounds, or just spraying people. They come with a life time warrenty, and the packs have lots of variety. They also make in line water filters that's made to attatch to the system. They have a charcoal filter that makes all water potable. Viruses, crypto, and bacteria proof. best filter I've found (inb4 sawyer, which can't filter viruses)
http://www.geigerrig.com/hydration-packs.htmlCheck
woot.com regularly too, because thats where I got mine at 50% off.