I really prefer the Platypus bladders, because of the large ziploc opening. MUCH easier to clean and dry (and put ice in, if you like ice). Unfortunately they no longer make a carry pack, but most third party hydration packs will fit one of their sizes.

If you run, I can't say enough good things about the Nathan Intensity pack. But I don't know how well it would work for cycling - my instinct is that one of my Platypus packs would be better.