Let's summarize what we've learned so far:
God created an "angel" knowing he would become the source of all "evil" in the world.
God could, of course, have overpowered that angel, but chose not to because free will is so crucial.
Human beings get punished (eternally) for exercising free will by giving in to that evil.
God loves us.
We need to be "saved" because one person chose to disobey god.
God is perfect.
If we happen to be too stupid to believe in him, or, unlike MathewT, not fortunate enough to have been born into a cuture that recognizes the "right" god, we get punished eternally for never figuring it out.
This eternal punishment applies even to someone who spent his life helping others, while eternal joy awaits any rapist or serial killer who repents shortly before death, as long as he's sincere about it.
Because god loves us.
And is perfect.
The earth is thousands of years old and not a few billion.
Dinosaur bones are thousands of years old and not hundreds of millions.
Hitler was a great guy and a brilliant but unappreciated visionary because of some horrible and unfair PR.