I come from a bad background which unfortunately has not provided me with the development/sanity/support to learn physics and philosophy or whatever the way I might of had these academic interests been able to spark when I was growing up so this question has been on the backburner a lot of the time while my mind atrophied due to hiding away from the world I have not found myself equipped to deal with.
Have you ever wondered about those famous people who with a slight change in their circumstances would have likely never contributed anything of note, how the stars have to align for a person to fulfil a lot of their potential?
I've digressed, I very briefly summed up my thoughts on the nature of existence on a blog from an elderly (outwardly atheistic) Melbourne Catholic priest called Father Bob who co-hosts a radio show I listen to.
His question was "What does death mean?" and rather than let my response go to waste on a theologian's blog (what was I thinking) I'll preserve it here.
Maybe this can be answered by looking at the nature of existence.
If I can borrow a phrase from Carl Sagan "we are a way for the universe to know itself" i.e. the universe is conscious in the form of ourselves ("starstuff contemplating starstuff"), so in a way the universe is conscious through six billion simultaneous consciousnesses, just considering the Earth.
I've always wondered what makes me me (why am I in control of this body and not some other consciousness), and if I had never existed would the universe in fact never exist; perhaps this is true because I am the universe (one small corner of it) so for me not to exist would be for the universe not to exist. This touches upon another related question of why anything exists at all, my current answer is that that all this around us is simply so that something is here (intelligent life would be the ultimate affirmation of this) although the price is it's temporary nature. Look at the case of "virtual particles" that can arise out of nothing and collapse back but only as long as it's within an incredibly short space of time.
If we were to all ask ourselves "who am I?" we could all say "I am the universe". So if you or I die this consciousness that you and I experience will still be here as long as the human race is around, or by extension our alien friends on the other side of the universe as there has to be at least one. The curtains will finally be drawn when the last star burns out and universe can no longer support life (but we may be one of many universes).