I prefer the Platypus bottles (MUCH easier to fill, clean and dry), but I just saw on their website that they don't make packs any more.

I read something on the LA Times site not long ago about a hydration pack that's actually sprung so it allows air flow between your back and the pack. That's my main issue with them - if it's hot enough to need one, it's too hot to wear one.

.... searching back to find the brand name... Ergon Bike - it's expensive and you have to supply your own bottle (that's where the Platypus comes in) - but if I had it to do over again I'd *definitely* want to at least try that one on. It sounds wonderful.