Originally Posted by
ekys
I'm a regular SFO-SYD flyer (3 round trips since September 1st) which is about ~14 hours (plus my connection).
I have traveled E- and E+ and without question, E+ is the way to go (I'll be careful not to say you won't make it without E+, that can be taken literally

).
With that, my strategy:
1. Ipod/iphone (with movies).
2. Laptop (my battery gives me ~4.5 hours with a dim screen and I watch movies or play a game).
3. Books. (usually I bring two, one being a lighter read - concentration levels change depending on how tired you are).
4. Magazine/Paper
5. Inflight Entertainment (I've survived without this, may last round trip showed movies I'd seen between my previous two round trips so I watched nothing, but usually you can eat away 4 hours, best around mealtimes).
6. Sleep - usually I get 4 hours.
It's not great but another option is to get a strong sleep aide and use that. I'm against this myself, but some colleagues swear by it.
Plan for the worst, hope for the best. The above outlines very well what you should do/bring on that flight.
I've flown LAX-SYD r/t twice. Once on Qantas and once on V Australia. On QF, I flew back on a broken seat (it wouldn't recline and the cushion was messed up and at an angle that was quite uncomfortable). The flight was 100% full and they couldn't move me anywhere. I survived OK. Watched 3-4 movies (2 for the first four hours, another one or two a few hours before arrival). I napped as well as I could manage. I walked around a bit. Talked to an FA a couple of times. Listened to my iPod. Ate when there was food. Stayed hydrated.
I can't remember being overly angry after we landed. But I can't imagine a situation that would be much worse than this (outside of turbulence and other rare factors).
The best was flying on V Australia and getting three seats to stretch out on and sleep the entire time. Who knows, you may be lucky or, as other have pointed out, snag an exit row or a better than average seat. Bottom line, you'll be fine. Even on United.