This is part of the hilarious idea of religion and heaven/hell, do you really want a eternity in heaven, honestly, what is there to do you would enjoy doing FOREVER.
Sex would be boring if you did it every few hours for the rest of time, as would bowling, reading and anything else anyone can think of. I'd prefer to stop, eventually as at some point there is literally nothing left to do, theres only a finite amount of things to do and see on earth. If we didn't have to work for 2/3rds of the day for 2/3rds of our lives, well, we'd be bored to tears, and most of those who work for so long are doing jobs that mean nothing to them and are boring. We've filled up our lives with so much meaningless crap anyway, you could condence the interesting stuff that was worthwhile and fun, into several years most likely, skip the rest and be done.
Then selectively erase the memory you wish to experience again as new, if technology was sufficiently advanced and we ended up in some kind of utopian civilisation then most issues like this could be dealt with, almost anything can be done if its possible and you had the knowledge and technology to do it.
I'd like to live forever, or die, come back as someone else, of course, you'd not realise it... But I find the idea of nothingness for eternity horrifying even if we would not realise it, it just seems odd, can't imagine it, just can't get the mind around it.
Horrifying? Seriously? I don't think you've really thought about it and taken everything into account, taking a more logical view of what we know about reality, you might want to reconsider living forever whether by advances in technology or a kind of reincarnation in time and space, first off presuming your individual conscious existence is a one off chance of incredible odds, you've been quite unaware and unaffected by your previous non existence which has lasted for a unimaginable amount of time, would you really want to experience the chaos of the universe since the big bang and possibly before?
Next let's say that science comes up with the technology to give you billions of years to live, let's say after millions of years eventually the civilisation on earth will be wiped out or moved on, perhaps you escape on a spaceship, next the sun goes, then the stars in the galaxy go out, after billions and trillions of years all that will be left is black holes and the void of space, eventually the very matter your made of will break down and essentially disappear, so you'll die one way or another most likely, now you have to ask is being conscious for all those trillions of years worth it, because who knows what may happen both good and bad in that time?
Now here's the really weird bit that goes along with your wish for essentially eternal consciousness and i have to say it ain't likely good overall and may be quite depressing and even scary to think, we know that we can consciously exist at least once because here we are, so whos to say it can't happen again?
No im not talking in a spiritual soul sense although it's possible, no in theory it's possible that time and space are infinite and it means that in infinity all possibilities can happen, which means that given enough time you can consciously come into existence again in some form, you won't have past life memory to know it but whatever things that come together which makes you you could and should happen again given enough time, which means in infinity if you die from your point of view trillions of years will pass in an instant, universes will pop in and out of existence but eventually and instantly from your perspective you will become conscious again in some way, shape or form and it will happen without end, you will get to experience everything as new again and all the good and bad the universe has to offer because all possibilities can happen, i don't know about you but non existence sounds preferable to consciousness without end.