When I was a child, and was told something or another about heaven, the way I chose to imagine it was as an infinite freedom to play GameBoy. Now that I am a man, I think this might be a better description of the other destination. Nevertheless, our present conceptions of what would make us happy can be a helpful tool for discerning where our heart lies, what we really long for, and whether or not these longings are properly ordered to our happiness.
Another angle for addressing the same question is to consider our frustrations. What is getting in the way of my happiness? What longings do I have that are unfulfilled? What can possibly satisfy me? One beautiful meditation on this theme comes from a source that might at first appear surprising as a locus theologicus: YouTube.