I don't. I think you either just disappear, like you're asleep, or something close to what Buffy has described, except not really heaven. It's more close to the stories people who died clinical death tell. There's a tunnel, a bright light and you're pulled into it, and then there are many stars, and you're one of them. Nothing has form or gender including you, but you still know you're you (like Buffy says). You're surrounded by many loveale presents, again with no actual form or identity. You're part of the universe. And your life, your family, your experiences, everything, seems like a dream. Like it never really happened. And you feel warm and loved and safe (again, just like Buffy says). You feel home.
That's the true heaven in my opinion. It's not a place. It's the feeling. But I wouldn't call it heaven, the place you're in. You just merge with the universe. That's why I don't believe there's Hell either. We're not judged, there's no one who judges you after you die. No matter what we did in life, we're loved. We're free. We're back to where we came from.
Either that or you're worm food.