I have a Camelbak (Mule) that I use for mountain biking. Its big enough to carry clothing, food, tubes, tools, map, first aid kit and strap helmet or armour to the outside. It also has a 3L bladder. My main problem with it is that if the bladder is full it makes the whole back of the sack sort of round and doesn't sit flat on your back and therefore is difficult to get tight enough to stop moving about (not so bad on the bike but not good when running). Also as you drink the water, it starts to get loose so you have to keep tightening it. You also have to stop to take anything out instead of just spinning a bumbag round to the front. I'm still trying to make my mind up whether to stick with the bumbag or use the Camelbak.
As for cleaning the tube...here's a handy tip although I prefer to use Milton solution instead of nuking it.