I have experienced great success with the Camelbak products.

This model has plenty of little pockes, lashing points, and compression straps. Oh, and it holds water. <img src="images/graemlins/smile.gif" alt="" />

If you want less conspicuous it is available in black

For complete "innocents" try one of these Although I do not have personal experience with this model so I don't know about pockets.