As a mountain biker my Camelbak is pretty much always with me now when I bike, certainly on most commutes and often on a road ride. It's comfortable and now I barely feel its even there (mule). The only issue I have is some days it's just not quite big enough ... Sometimes I need to ferry a pair of shoes, clean towel, books and occasionally a laptop.
But that means a bigger pack or panniers or courier messenger bag .. None of which I like! Fussy bugger that I am. Am I alone in resenting swapping all my bike stuff into yet another bag ? Often I am transporting this extra kit just one way on the commute so the return journey leaves the bigger bag flapping all over. I want to ride light.
Maybe grumpy old man syndrome is here! Is it me? 
)
