I think that on a "personal self" level death probably is the end - like you said a deep sleep of nothingness - much in the same way we have no consciousness of existence before we were born......
but on an atomic level we are recycled - or reincarnated if you like - simply put the atoms that form me or you will one day be part of other bodies and other lives.....whether or not that constitutes a continued consciousness i dont know - i guess it depends if consciousness exists at an atomic level......

its kinda a headtrip but if you ever get the chance to read Bill Bryson's "A history of everything" he outlines scientific opinion on the matter.....its reckoned that if you choose any person from history (at least a couple of hundred of years back to allow the atoms to get through the ecosytem) then you will share some atoms with them - whether that's Jesus or Atilla the Hun....so basically humanity is a shared experience linked by our atoms....which i find a kinda reassuring idea