On short runs (warm days) about 5-10k, I'll use my hand held Nathan waterbottle below:
I love it, as it has a zipped pocket for gels and keys etc. For runs/races of 8k or more, I'll take my Black Wolf fuel belt. The waterbottle sits at your back and there's a small zipped pocket for gels/keys too. The pocket isn't that easy to reach, but I've got used to it:Hydra Pouch. I find it very tricky drinking from the plastic cups while running and am now getting compettive enough (with my own times) to not want to walk while drinking:
For longer runs, where one water bottle isn't enough, or long enough so the fuel belt will be bugging me, I have a small hydration pack. It holds about 1 litre of water/gatorade and I can refill it at water fountains:
Both hydration packs have chest straps and pockets at the back. The small one has an elastic chest strap (good idea!) and a purpose made iPod/phone pocket with a water resistant hole for headphones. The larger pack has a chest strap and belly/waist strap, but they aren't elasticated. It has two pockets, but nothing made for headphones. I'll do a write up after I get to use it for real though.
Hope that's enough. I have a knee niggle, the tendons behind my right knee are a bit tight today and yesterday, so I've taken a couple of days off. Hopefully I'll get a relaxed run in tomorrow!