The Brooks handheld is ideal for carrying your fluid on long runs. It holds about 1pint (600ML approx) and has a pouch for gels or even keys! The main advantage over the doughnut style bottle is that the Brooks Handheld does not require a constant hand grip - the soft thin neoprene strap holds it in place so that you don't get aching fingers and hands. Oh and by the way, it fits for both left and right handed! You can see the accessories at www.brooksrunning.co.uk You can get your local Brooks stockist to order it and it costs £10.
Then there an article this month I thinkin runners world that says a lot of upper body injuries are caused by fist bottles! Apparently they throw your gait out as well and can cause other injuries. I bet the manufacturers of these water bottles love articles like that!
The Brooks handheld is excellent to run with. I have run 2hrs plus with it and had no problems. If it is throwing you out you can always change hands or use one on each hand!
Also, I would rather be hydrated then dehydrated on my long runs. The handhelds are very prevalent in US long trail races. I'm talking 100 miles and you never see people getting injured by their handheld bottles there! The handheld types are easier to carry than the doughnut ones aswell. Very comfy. I hardly notice mine!
I was given a 'water rucksack' (for want of a better description) as a Birthday present. I've used it once, absolutely useless. It took more energy for me to suck out the water than the whole of the three miles I'd run!!
I never take water with me on a run and never feel the need for it. However, when running in an organised race I always take some when I pass the water station (How much actually gets drunk is a topic for another thread!)
In a race i'd definately be drinking if I was running for 2hrs+ but for training? Not so fussed.
Perhaps a slightly backwards mentality to what some of you practice but when training I don't really like carrying a bottle around and I'm not really bothered about ensuring I'm hydrated for optimal performance. Okay common sense says to make sure you're not going to keel over and die from dehydration, but didn't some great runner once say something about training under unfavourable conditions makes things easier come race day?