h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

There was a philosopher (French Logician I think, but am not sure) who gave a similar argument for believing in God. Either God existed and you believed in him, God didn't exist and you believed in him, God existed and you didn't believe in him, or God didn't exist and you didn't believe in him (I think that's all 4). If you didn't believe and were wrong you got eternity in hell...which kinda sucks. If you didn't believe and were right then nothing happened...which still kinda sucks, but not quite as bad as hell does. But if you did believe either way you either broke even (God doesn't exist and nothing happens) or won big (eternity in heaven...long robes, harps, endless food/drink and beautiful houris (sp), Battling thru the day and feasting at night...whatever you're into really). So it was obviously best to just believe...just in case.

The problem is...is this really good enough if it comes down to it (ie God calls you up and you have to answer for it). That's something that ol' Kierkegaard got into a bit

The bloke you're after is Blaise Pascal, and more specifically, what's come to be known as "Pascal's Wager". It's essentially a somewhat less convincing argument for the existence of God than what some others have come up with (St. Aquinas, St. Anselm being two notables here).
The biggest problem seems to be that using argument to prove the existence of God doesn't work, because you're so bogged down in using the correct formulation of words (the definitions of which being at best symbolic and at worst completely inadequate) that the actual meaning of what you want to express is badly diluted, if not lost altogether.