For me or the kids?
My kids (6 and 8) are actually really good at the long haul now. My family are all in the US, scattered about, so we fly pretty often. They each take a backpack with:
DS/3DS and some games
ipod touch/my old iphone
earbuds
Kindle Fire (this one was a new one for my daughter on our last trip, and soooo useful)
2 books
1 activity book
reporter's notebook
pencil case with pens and pencils
a couple of small toys in a small, sealable bag
a couple of snacks
a refillable water bottle
a brand new kid's magazine
Even without the entertainment system most flights have (yes, I'm looking at you American Airlines), they keep themselves pretty well occupied now. I bring a few extras (stickers, extra magazines, my ipad with some other films I know they like, pipe cleaners) I haven't actually had to bust out for the last few trips.
For me, the entertainment stuff is pretty similar. My phone, my ipad, my kindle, 1-2 paperbacks (for when they won't let you use an electronic device), a couple of snacks, a puzzle book, and pencils.
I have found the travel sickness tablets my son and I take pretty helpful in getting off to sleep. I won't take them when I'm alone with the kids, but they are great if I'm travelling alone or my hubby is coming with.