According to the United States Declaration of Independence there are three examples of unalienable (or inalienable according to earlier drafts) rights that were given to all citizens and should be protected by the government: "Life, Liberty, and the pursuit of happiness". Unalienable means that these are gifts that are unable to given or taken away.
While all three of these unalienable rights are important and you can argue that losing any of these wouldn't be ideal, it could be argued that you can't have liberty or pursue happiness if you are not first given life. So life could be the most important of these unalienable rights. On the other hand, do you really have a life without the other two: liberty and the pursuit of happiness?