I'm glad you wrote about this, it's such an important topic that I think a lot of people never really consider. I'm registered for organ donation, which to me is the most obvious thing ever - some members of my family are surprisingly squeamish about it, although luckily my parents both feel as I do. I'm also registered (well, I will be when I sign the forms) to donate my brain for research into neurodegenerative disorders. The link for more information is http://www.iop.kcl.ac.uk/departments/?locator=380. I don't yet know if that's compatible with organ donation - I'm trying to find out - but if people are unable to donate organs then it's something to consider. I don't give blood, unfortunately - I did once, fainted, and was told that I shouldn't ever again because it was dangerous for me. Still not entirely sure why - it can't be unusual to faint after losing however much blood it is that they take - but there it is.