I use Platypus products and have had no complaints. I even use the Big Zip hoser as a "poor man's" Camelback. I like the large zip-top feature, and have never had a closure failure cause any leaks.

HOSER: http://www.campmor.com/webapp/wcs/stores...mberId=12500226

These are also pretty sturdy. Take a look at their refillable tubes, too.
http://www.easytravelerinc.com/index.asp

None of my roll-ups last as long as a Nalgene hard bottle. They eventually develop a tiny leak if they've been creased too often. However, I plan accordingly and replace as needed.