I always carry plenty of water even on short hikes. I learned that the hard way! Fanny packs are fine but can get pretty uncomfortable on longer hikes. They can also get pretty hot as there is usually no ventilation between the pack and the fanny. That's not to say I don't ovten use a fanny pack.
My regular backpack is a Deuter with a 3L bladder. It has all the right straps in the right places to make it comfortable. However, it is too big for short hikes when I have just small things to carry.
I have a Coleman hydration pack which was very inexpensive and works very well. However, it has no room to carry even small things.
I just got a Camelbak with a 3L bladder. It is a Camelbak M.U.L.E. and it is great. It also has 600 cu. in. volume to carry small things. It has large shoulder straps and a well ventilated back. It is very comfortable but is pricey at $71. The bladder is pretty well insulated and I am thinking if you freeze half a bladder the day before a trip and fill the rest the day of the trip it will stay cold all day. (at least not hot) The pack itself only weighs 1 lb 14 oz. I have also seen Backpacker magazine test the bladder by taking a mostly full bladder and running over it with a car. It did not burst.
I will have all these packs and others on display at the event in Kingsport on April 18. The event is GC1N3ZP. I will also have several tents, bivys, stoves, and other things used in hiking and backpacking.
I just realized I sound like a salesman

. I am not selling anything just showing the things I have collected over the years. Everyone is welcome and I promise not to talk too long.