There is no ultimate answer to the meaning of life, grand goal for humanity, or ideal morality. This is because a definitive answer cannot be given to a question without regarding the topic objectively and it is impossible to regard 'life' objectively as we are within it. In other words we are not able to express the question in terms that share a common frame of reference with our normal lives whilst outside of the universe of discourse. There is no loophole to this. You can not say "God knows the answer" on the grounds that a metaphysical super-being could have a privileged objective perspective on life, the universe and everything as this god would be part of the people's spiritual life. Ironically it is the very fact that people believe in some sort of God that makes it impossible for such an entity to take a independent, unbiased, definitive view.
Conversely, if no one in the entire history of the universe believed in God this God would still not be able to ask the question, as this lack of knowledge of metaphysics and spirituality in culture would be such a serious omission from the universe of human discourse that even if the answer to the meaning of life did not depend on such foundational concepts you couldn't be sure that the answer God had arrived at without us having knowledge of God was complete. Everything has to be under consideration in a question for the answer to not be in doubt. You can not exclude a bunch of concepts even if they have no bearing on things, you must include everything that is known and in this case God is in the awkward position of knowing too much.
I can't prove God doesn't exist, but I prefer to believe that there isn't one. I prefer to live in "reality" and a 'God' is definitely intangible for me.
However, I am not a Nihilist. Just because I have proven that the question:
"What is the meaning of life?"
is erroneous (not unanswerable and mysterious, but simply semantically flawed and fundamentally impossible to ask), as I find the whole notion that it doesn't ultimately matter what humanity achieves, or how we should act towards each other, or what we should worship, etc. is incredibly liberating. There is nothing, ultimately, stopping me from attempting anything. I don't feel as if I ought to be doing 'X'.
That said, I have adapted over the years to cope with other people and have found that the application of:
Good Manners,
Tolerance and
Avoidance
in roughly that order, has worked out rather well.
I don't need to follow some Bible or even the Law of the land as the things I tend to do fall well within acceptable behaviour - i.e. I do not feel like murdering anyone, so telling me I will go to prison, or Hell, if I do doesn't have any effect on me (I wasn't going to anyway).
Finally, this ultimate meaning of life is all to do with the 'Eternal' which I am not interested in. I am far more interested in the short-term, those things that you forget, or will be erased by History. I speak of the often overlooked 'Ephemeral'. A nice ice-cream on the first sunny day of the year, or just a decent cup of tea when you really feel the need of one.
Don't forget. We can all make our own meanings within our lives. Things to live for, goals to accomplish. However, as all of these ultimately fall into the class of the Ephemeral (as far as humanity is concerned), none of us should think that their (way of) life is better than others. I will include myself in this and put this alternative viewpoint forward of a life without God, meaning, or karma as a polite recommendation for some of you to consider as it has worked well for me, however, I respect your beliefs and opinions on life if you choose to ignore this.