You're perfectly entitled to feel that way. There's no objective set of human incentives/desires and everybody is entitled to his/her own utility function. For me, I'm too curious about what the future will bring to die now or any time sooner than is necessary. Learning, satisfying my curiosity, and gaining new experiences have thus far provided me uncapped positive utility and I expect to continue to feel that way into the indefinite future. If I didn't have that love for science and technology, I could expect that long life would become monotonous. The only opinion I won't abide is that of someone who not only doesn't want to live longer, but also doesn't think I should be allowed to.
If you don't like it, you could always choose to die. The point is that these technologies will give you the luxury of the choice to live as long as you want.
Personally, I've tallied up a number of things I want to do in my life, and after having done 2 big ones (well, one finished and one still in progress with a moving goalpost), I've realized just how long it takes to accomplish big goals. Even my incomplete list far exceeds 200 years already. I'll take the life extension, thanks.
I just feel like turning when I die into a luxury option somehow trivializes my entire existence. I know this is just a personal hangup of mine, but I feel like I am nothing but a summation of activities if I know it's time to die when I get bored with this now-plentiful lifetime. It's like, if you could just keep disney world open as long as you wanted, you could get to ride everything until you were sick of it, and then you'd finally be happy and ready to go home. shrug Maybe I am just uncomfortable that that level of control. It's definitely pressing a lobe in my brain I don't have a name for. I'm sorry I can't be more articulate than that but I know it's based in some rat-brain non-rational fear. It's interesting.
According to various philosophies and religions, defining life in terms of "doing" is one of the fundamental errors, and it does have various negative implications if you think it through to its logical conclusion.
So, no, I don't think this is just "a personal hangup" of yours...
Any thing you define life in terms of is a fundamental error. There is no meaning except that which you make for yourself. You can define it in terms of what to be, or what to do. If you define it in terms of what to do, life loses meaning once you run out of things to do. If you define it in terms of what to be, you end up in an ego contest with anyone else who wants to be the same thing, and life loses meaning once you become "common".
Religion dodges the issue by presenting goals that cannot be reached, which I think is a fair compromise for most people.