Here's another way of looking at the likelihood of an afterlife, besides the materialist approach I mentioned on page 2. Is there a God who cares about us? Some people think so. They think they see evidence of his love in their lives. But many posters here have agreed that it doesn't make sense that God would watch over some people and completely fail to show himself in other people's lives, nor to help all the people who really need help, living in desperate circumstances without enough food, clean water, etc.
So, if there isn't clearly a God who cares about us during our earthly life, "glutted with agitation" as it is, why would he have prepared an afterlife for us? Is that really logical, that he lets people suffer through all kinds of awfulness here and then says, "But surprise! Now that you're dead you get to live in this nice other world that I prepared for you. Sorry I let you starve to death in the last one/get murdered with a hatchet in the Rwandan genocide/etc., that's just how things work."
I suppose some people have a more open-ended, Buddhist kind of view of the cosmos, where the spirit is just something that lives on, or is reincarnated, which leaves all kinds of unanswered questions about why it works this way, if there isn't a caring personal God who designed things to work that way.