Kindle
Advil PM or whiskey.
(Never at the same time.)
Depending on the airline, you might not get free booze anymore. I know United did away with it in coach on international flights a few years ago. Personally, I don’t drink or take sleeping pills as I find that they make my jet lag worse. I do stay up late the night before to try to sleep on the plane, but even then I usually manage just a couple of hours.
Repeat after me: Ambien is your friend. Sheesh, man, that could be a 2 hour flight. Although i would do a trial run of am bien first (or zopiclone or sominex) as *some *people get some wierd side effects.
I just did Seattle to Amsterdam last week. Was asleep after the meal and woke up for the descent both ways thanks to my friend. I remember the 15+ hour direct flight I had from Atlanta to Shanghai in the back of the bus. One and a half Ambiens and it was a two hour flight that was “too” short to finish my book.
Otherwise, I always took a lot of books. I’ve done at least 50 transpacific flights and probably more like a hundred in the past 25 years.
Other thing is to have a music player with noise cancellation earphones, ear plugs (for when you sleep), eye shade and the neck pillow. Actually, the neck pillow really is the number one accessory for me otherwise I always wake up with a sore neck.
A Nintendo DS or other hand-held game. They do sell games for grown-ups, although I passed a very pleasant 3-hour flight playing my 7-year-old’s LEGO Indiana Jones 
This is one of the reasons why I really like the long-haul Airbus - IIRC it’s the A340. It (at least the SAA and Lufthansa ones I’ve flown in) has a little area down a flight of stairs where, apart from a bunch of toilets, there’s a water dispenser where you can get as much water as you need without having to keep on calling the flight attendant.
Nintendo DS. A few books. Ipod. I also will attempt to strike up a chat with my seat-mate if he or she seems amenable to such a potentially awkward exchange.
Science From Your Airplane Window