1. Most likely (and hopefully) old age
2. some respiratory disorder - I used to have asthma and my two uncles both had pretty bad respiratory problems. So when I get old, my respiratory system probably will be the first to deteriorate.
3. heart or something - I love creamy (fatty) things, though in general my diet is rather healthy.
Yes, I know this is a rather morbid topic, especially with some mentioning suicide. Sorry about that.