I find this question very mind boggling, and really fun to think about. This conscious mind I have, to my knowledge, has existed for twenty some odd Earth years. After I die, my body will decompose into simpler and simpler states of matter. The electrons that are in my body at this given moment will find their way to the far reaches of space. I will not exist as I am in this body. If I have a spirit, then the possiblilties after death of the physical form are limitless, and I will most likely be wrong, should I try and understand what existence will be like after I have passed on, for I will be given keys to doors I don't even know exist now.
But should their be no soul, I can see 'me' as easily being a collective 'us'. After all, my parents supplied the blueprint to create me but I am not only from my mother and father but of the animal I eat, the air I breath, and the heat I absorb. An electron does not stay in one place for long, or at all. So I am just many other things that change form to upkeep 'me', conscious mind. When I die, I will never exist again. The only possibility I can see of existing again would be if someone were to find and construct every single bit of information that composed me at a given moment, and only the piece of that single moment. Every electron and every quark. Maybe I wouldn't need what composed my legs, but what ever makes my conscious thought 'me' at this moment. Only then could I begin information transfer again, but I would of course not remember what happened to me after that moment in the past. Kind of rewriting my future.
Anyways, back to my idea of an 'us'. Once I have died, parts of me will surely compose new creatures who will walk Earth or some other planet. Though my conscious mind, which is a one time thing, will never interact with the universe again, everything that made it up will contribute to the development of new minds elsewhere. Since in this theory the mind and life is nothing more than beautiful chemical reactions which make matter aware of itself, then together, we are Universe. In an essence, we are God. And when we are searching desprately through this life for an omnipotent being, all we are really doing is looking for the rest of ourself. The rest of 'us'.
Another idea I like, but isn't completely origional thought, is that we are each our own universe, much different from the one we observe, that must latch onto the one we interact with to inport and export information. Once we die we may become isolated until our universe starts interacting with another.