This has been an issue for me for as long as I've been flying. The question is whether I should recline my seat back, increasing my comfort but inconveniencing the passanger behind me.
I've always felt like if we could all just not recline them SO dramatically we'd all get along better. I tend to not recline my seat because I ALWAYS feel bad for the person behind me, as I project on to the them the annoyence I feel when the person in front of me reclines their seat.
So I find myself usually the only one on the plane with his seat upright... ready for landing... even though there's still hours left on the flight.