Hello PSW,
I am an ultra-long haul flyer. Here's some of the things I do.
1. Read
2. Sit in the Virtual Cabin and look out the window (really realistic)

3. Listen to my iPod
4. Chat on MSN
5. Eat
6. Set up my sleeping bag next to my PC so that when ATC gives any instructions, I quickly obey them and continue onwards.

7. Kill ants

8. Study (sometimes)
9. Watch TV (turn PC speakers on full volume)
That's most of the stuff I do on long-haul flights. But I only do ultra-long hauls once in a while, like once a week usually on Saturdays.
Hope this helps,
Ashar
PS: What route are you flying? My favorite flight is London-Sydney. I usually stopped at Dubai for refuel. But now, I use my 777-200LR for non-stop flights.
