While pondering this dilemma, I came to a startling conclusion. As people have longer lives, they would become more hedonistic, not less. Nowadays, vast resources are dedicated to how people remember you. Monuments, huge donations, etc. When no one is looking forward to death, or trying to live a good life (I've got 2500 years to become a better person!), everyone will likely go nuts. Expect to see billionaire 130 year olds trying to pick up 19 year old girls in bars.
Of course you have to take in effect the fact that people would be less likely to do stupid things that get themselves killed. After all, if we take the maximum age of a person to be something like 10,000 years, then the murder of somebody who was only 100 years old would be similar to the murder of a 10 year old respectively.
Living forever would fucking suck, pardon the language. And I have one question for you. What if you don't make the cut off?
Then I die I guess, without having lived my life to the fullest enjoyment possible. Of course as it is with what I know of the world it would be almost impossible for me to live life to the extend that I want to, there will always be something more that "I wish I would have done" before death took me. I know that regardless of how well I do in life I will probably never get to stand on the top of Everest, I will never get to stand at the south pole and say "I am at the bottom of the world", I will never have the years required to study on the banks of the Ganges River, I will never be able to travel to the moon, or mars; I will never be able to wake up and look out the porthole of the international space station at the earth floating os far below me, I will never walk the Great Wall of China. Sure I might be able to accomplish some, maybe even most of it before I die, but there will always be something out there that I want to do but haven't done. And with the knowledge that I have of the various technologies in existence today, I am willing to wager 90 years of doing what I want for the thousands of years I could have.
And would it suck so much to live forever? After all it's not that everyone you know is dying, since they are living forever too. It's not that life is hard to live or tiring physically, because as science advances we should reach the point where we can give you the body you have now or in the "prime" of your life, probably one even better (gene therapy and similar treatments have already been used to cure genetic problems and failing muscles, joints, and organs in primates, is it so far of a leap to apply that treatment to humans?). So you suffered trauma in your life? Well you now have thousands of years to get over your problems and move on, for medicine has shown that time heals all emotional and mental trauma given long enough. The only real problem I see is boredom, and society has reached the point at this time where content is being created faster then you can absorb it (I know at least two fanfiction sites where they are gaining over 150 words per second on average), and as you are you physically can not absorb information as fast as it is being created, and should you change physically to be able to do so it is only fair to assume that the content creators will speed up as well. That basically covers all of the reasons listed on tvtropes' "Who wants to live forever" page, so if you have some other reason why living forever would be so horrible feel free to point it out. I don't see any right now though.