Oh Lord... Why am I joining in religious discussions again? This cannot end well.
Anyway, as a Christian, I can say that while Pascal's Gambit may make theoretical sense, there are a multitude of problems with it:
1) God knows your heart. If you choose to believe solely for Pascal's Gambit it won't work. Because in your heart you'll know you aren't REALLY sure that he's real; you only know that the benefits if he IS real outweigh the negatives if he isn't.
2) For atheists it makes no sense either, even if you don't believe point one. Athiests are generally absolutely sure there isn't a God, in which case the math doesn't work out; in their case the expected value is negative for believing and positive for not believing since they believe the chance that there is a God is 0*.
*If you don't, I count you as an agnostic.
Good reasons to be a Christian are plentiful, but Pascal's Gambit is not one of them.