Blackhawk hydrastorm reservoirs are my favorite - BlackHawk HydraStorm Anti-Microbial 100oz Hydration Bladder

BlackHawk is my favorite brand of reservoir of the ones I've used. I have three or four of them now in various packs/daypacks and have not had any kind of failure or problem. My only (little) complaint is I wish they had some kind of hook at the top center so it would be easier to secure them in other brands of packs/bags.
Pros: Insulated tube, welded baffle keeps it flatter when full
Cons: Needs a top center hook for using in other makers' bags/packs, bite valve a bit hard

This review was written in the old system and had content requirements that are different than reviews written today.