9mm vs. .45 ACP

[Ron Burgundy]

I'm looking to buy a handgun for self defense. I can't decide between 9mm and 45. I'm planning to get a Glock because of their reliability and affordability. But if you think something else is better, post it.

I'm not an experinced shooter, and I don't plan on spending a huge amount of time practicing.

I'm assuming the 9mm is easier to shoot, but the 45 has better stopping power. Is this correct? Are there any other factors to take into account? What's the difference in price for the ammo?