The Trouble with Pascal's Wager
As has been pointed out by many others, a difficulty with Pascal’s Wager is that it has no real way of dealing with multiple exclusive beliefs, each threatening hell for failure to adhere to those beliefs. Since each belief is threatening an equivalent amount, the Wager results in a stalemate.
What I haven’t seen pointed out before is that this works even within the context of the sects of a religion, and how the existence of these sects creates a kind of nesting system with strange implications for the Wager. Take the Westboro Baptist Church, or one of the innumerable tiny denominations that are scattered throughout the world that have similar enough beliefs. Since the Westboro Baptist Church preaches the typical Protestant Christian soteriological schema (forgiveness of sins through faith in Christ crucified and resurrected) most Protestants would believe that members of the WBC will enter into paradise when they die (even if they belief them to be horribly incorrect in many others ways). At the same time, members of the WBC would say that nearly every other Protestant will enter into perdition when they die. Given this, the Wager would suggest that nearly every Protestant should join the WBC in order to hedge their bets. Which I would expect to be wholly unpalatable to nearly every Protestant (or at least I really hope this would be the case), and so they must reject the Wager as a sensible way to make decisions.
Indeed, the basic premise of the Wager seems odd when you spell it out explicitly: whoever is threatening the worst afterlife should be who you join up with, and then within that group whomever makes the most exclusive claim (what happens when two sects are equally but mutually exclusive?) The implication seems to be that if ever a religion cropped up with a more horrific afterlife than hell as part of its beliefs then Christians should jump ship. You might protest that hell is already, by definition, the worst possible afterlife (since that’s usually how it's defined). But suppose a religion crops up called the Heartbonders, who believe in a similar paradise/perdition schema, and that adherence to the beliefs of the Heartbonders is necessary to avoid perdition, but with a twist. The Heartbonders believe that every human has a soul twin, and the only way to enter into paradise is for both soul twins to enter into paradise. Which is to say that if your soul twin is a member of the Heartbonders they will still enter into perdition should you fail to join up. So not only will you condemn yourself to hell for failing to join, you condemn another. The Wager seems to suggest that Christians should join up with the Heartbonders, since their afterlife beliefs are more threatening (not to you mind you, but if we consider harm to others to be sufficient for a “worse” afterlife then it all works out).
So I don’t think Pascal’s Wager is a sensible way to make decisions for yourself.