Some would say that what you want is not happiness, and that getting what you need is different. Getting what you want instead of what you need is going to leave one unfulfilled and depressed.
Sometimes what you need doesn't exist, what you want doesn't exist either, and won't make you happy, but at least you can try for it...
People talk about digitizing one's brain to live forever. But, the digitized version of yourself would be inherently a separate person. We can't move your conscious self. We could copy it, but the computer wouldn't be you.
That assumes that you go from one person with one body to two people with one body each. If you instead assume that you become one person with two bodies then losing the original is the same as losing a limb. Awkward, but no cause for metaphysical horror...
It's extremely hard to copy the mess that a human mind is, but one can change their mind so it becomes transferable.
If you change your mind then you have lost your former state and arguably lost your 'self'. This is why I detest the thought of heaven, it just doesn't work without messing up the individual who 'goes there'...
I have no wish to be human, in fact I loath humanity and find even being partially human terrifying and detestable.
You are correct in that the culling and condensing of the self I have described here will exclude you from humanity, I do not consider it a loss. Humans are abhorrent.
Try as you might it would seem that you are still significantly human, and if you manage to forget about being human you might realise that you can't completely dismiss your humanity without also losing much of what you value about yourself. Letting humanity dictate your goals will blind you to your own ambitions...
There really doesn't seem to be any current means of discerning the facts of death, so I suggest that people simply choose whichever assumptions suit them, but I would suggest checking that the theory doesn't have any glaring holes.
Assuming that you simply stop would imply that you don't care about it any more, which comes out fairly neutral.
Assuming a judgement leads to needing to follow arbitrary rules in life to achieve happiness in death. Fairly good but has a high cost in term of limiting freedom and a complete absence of personal morality...
Also, it involves a certain amount of horror, if it is a place then it probably isn't feasible, if it is a state of being then you probably wouldn't recognise yourself...
Simple perpetuation could be frustrating, but also kind of exciting. But as with all excitement it will probably wear off, so expect to visit the wonders of the world, take a tour through Area 51, and then spend the rest of eternity haunting a TV...
I don't really see the point of reincarnation, I guess in the future the technology might exist to browse through your past lives, but you probably won't care to. It does offer that warm, fuzzy, 'you get to remain an active part of the world without violating the known rules' feeling, which has much to recommend it...
You actually do live forever, every time someone dies they simply split off from your reality and remained in one that they didn't die in. Life is pretty fragile, so the odds of being in a reality with someone particularly old are quite low and survival rates would be statistically consistent so it may go unnoticed, but just living to be 1000s of years old could lead you to pick up some rather nasty chronic conditions...
Bad judgement: god is out to get you and your only hope is to gain enough spiritual awareness to fight back. After you cut off gods head with a chainsaw you lead an army of space marines into the warp and become a god-emperor...