The only time I'll consider using a Camelbak on a bicycle is in the winter when it's cold enough to freeze my water bottles. If you're going to lug the water along on a ride, you might as well be able to drink it. Of course, I conceal it under my jacket. They are nice for skiing, however.

Yes, the fashion Nazis at BF have declared the lowly Camelbak to be a Fred accessory. Sorry.