Watch the hose. Today, the bite valve caught in my wheels and was ripped clean off -- I failed to notice. Because the bottom of the hose was lower than the bag, siphoning action drained the entire bladder. Miles later, I discovered I had no water more than 20 miles from home on a hot day. I don't make a practice of begging, but I made an exception today to fill the bladder. Made it home just fine.

Watch the hose. Today, the bite valve caught in my wheels and was ripped clean off....
I made a necklace out of a piece of shoestring, and tied another shorter piece around the tube end and the tube runs under one arm and gets clipped to the necklace with a mini-carabiner. If I drop it, it doesn't go far.
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you can get hose clips and simply clip the hose to the front of the jersey. camelback sells them.

I had a bladder in a FastBack Systems Double Century on my Volae and I was pretty sure that the hose would end up in the back wheel sooner or later. I was pretty attentive to its location, but you can't spend all your time checking on your hose. I sold the bike, but if I had kept it I was going to figure out a way to route the hose so that it wouldn't fall into the rear wheel if it came up attached.

I actually prefer bottles so on my Fujin I'm using the FBS bag to hold my gear and putting fluids in bottle holders - works better for me.

Some people like to use a retractable badge holder available at multiple places such as Office Depot. Just clip the metal part to the seat and clip the other end to the hydration bladder hose.
http://www.officedepot.com/ddSKU.do?level=SK&id=834344&Ntt=retractable%20badge&uniqueSearchFlag=true&An=text

I keep the hose tucked into my shirt. It has fallen a few times, usually when I drop it by accident. It's never become caught in the rear wheel, though!