I also plan to bring in a couple of bottles of drinking water, just to make sure I don't get too dehydrated.
Don't bother, just ask the flight attendants. Normally they will serve you extra on demand, including snacks (sandwiches, chocolate bars, fruits), even in economy class.
Also expect your drinks to be expected at the gate, liquids are now checked closer since they could pose a threat.
Long flights are a problem for me, never can sleep and economy class is just a pain for me. When I returned to Taiwan a few weeks back (from a holiday) I requested for an aisle seat and was happy to get one - but only on the shuttle flight, on the long haul flight they squezzed me in the middle row. :x
Anyhow, normally I try to kill time by watching all the movies available and reading a book or magazines. Drinking alc (wine) didn't help me when I tried it, instead it made me sick and the whole experience worst.