it is very likely that my ticket out will be Alzheimer's or another neurodegenerative disease. In that case, cryopreservation will only make sense if I commit suicide at the very onset of the disease and am frozen right away which may not be possible. If I get Alzheimer's I may as well donate all my money to SIAI or Africa.

Consider two possibilities:

1) Alzheimers breaks long-distance communication more than it does actual information such as memories. Cf moments of lucidity. It's not clear how true this is, though.

2) It may in fact be possible to undergo controlled legal death at the onset of death in some number of years. See the Oregon laws, which are likely to start to be passed elsewhere. See also http://www.evidencebasedcryonics.org/2012/05/09/revisiting-donaldson/

I want you to live too :)