What does one die of?

This question has bothered me quite a bit. What would I rather die of? Assuming most of us don't want to get killed in accidents or homicides, what would be an acceptable cause for natural death?

Let me lay out the basics here. I'm generally healthy, eat healthy, never been overweight, very fitness aware and generally active. I run 3 miles every other day and try to do a spot of weights etc during the week. I also take a 30 min. walk every weekday unless the weather prevents it. Statistically speaking (my life insurance agrees too) I have a reasonably long life to look forward to.

I know most of us make lifestyle choices to ensure at least probabilistically that they have a "good, healthy" life. Nothing wrong with that. Heck, I do the same myself. But regardless of my life choices, the guaranteed fate is death one day. Working backwards from the inevitable what will then make me die if I am perpetually fit? Do I want to wither away slowly - despite all my efforts to remain fit? Do I want to live long, not have any major diseases and then have my organs fail me (think about it - ears, eyes, teeth, kidneys, liver, lungs) one by one from the sheer strain of having functioned so long? Or do I want a shorter life and die in one swift strike of something major? Is there a golden between somewhere?

I suppose there is no real good answer; no technique of leading your life that will guarantee that you will healthy as long as you desire to live and then make a quick, graceful exit from the world. My guess (ok my adventure into spiritualism) is that in the end, we all should strive to have a meaningful life. Everybody has their own definition of meaningful but we need to have a concept that we live and abide by. That surely is in our control. For the things out of our control such as death, we can only hope for the best ....