For me, it's nonexistence. After reading through the Pauline doctrine and Thomas Aquinas' "Beatific Vision" doctrine, it paints the picture that Heaven is not some eternal cosmic resort of infinite human pleasure and satisfaction.
Your physical body after you enter the realm of the dead doesn't really exist anymore; thusly, your brain and your mortal mind are gone. Only your soul, your existential essence, remains. As for what happens to your soul, it unionizes close with God, which is said to be a fundamentally euphoric and deeply existentially wholesome experience.
The mystical point of view is that this causes your ego to dissolve under the weight of divine experience, while the rationalist point of view is that your ego does not dissolve, but rather you become so perfectly aware of God through the catharsis of heavenly ascension that it LOOKS like you don't have your own will anymore, even though you do. It's just perfectly aligned with God, so it's impossible to tell.
The modern folk interpretation of Heaven only became widespread following the Calvinist/Protestant reforms that split away from the models and doctrine of the old clergy.
I choose the Void. This material existence ultimately has nothing significant enough to offer to convince me to stick around for an eternity. God is the foundation of all existence, and as it is an indifferent (yet simultaneously caring) God that chooses to both love and to harm itself, so am I ultimately indifferent. I don't resist my humanity, though.