I don't usually drink during a training run, unless I'm doing 18 miles or more. I don't like running with a bottle in my hand, so I always buy one from the nearest shop.
During a run I always drink Lucozade Sport as that's what I'm used to, but if I'm running a race I'll have water if they don't have any sports drinks. If I'm running a marathon I'll always drink a full bottle at each water station after about 6 miles as when you are running that sort of distance it's better being over hydrated than dehydrated.
In the summer I do usually bring a few quid with me, even if its only a short run, so I can get a drink if I'm thirsty.
After a run I always have a pint of water, or a protein shake if its been a ridiculously hard run!
Hey Running for me, I'm training for the Nottingham Marathon too!
When I was training for another marathon I just went on the basis of a big meal for dinner the night before, breakfast, fruit/sandwiches/chocolate for lunch and then run in the evenings. Also plenty of water during the day. After the long or fast runs I used to have a shake too.
One bit of advice though: always have breakfast before going on a morning run. Long story short, I got injured during a morning run and and when they tested my blood/sugar level it was quite low. I'd had a shake instead of breakfast, but they said you should always have breakfast anyways.