Short version: whatever you expect to happen.

Slightly longer version: If you believe in the Christian heaven/hell and such, you'll end up there. If you believe in reincarnation, you'll reincarnate. If you're an atheist, nothing happens. But yeah, I tend to think you'll end up more or less where you're planning/expecting/hoping to go. I also tend to think... or at least hope that you'll also be able to see loved ones who have gone to different afterlives.

And I have no idea what agnostics get to do. Spin the wheel, maybe? I'd like to buy a vowel...