I came across this interesting website called: http://www.doyouneedvisa.com recently. Basically what it does is that you tell it where are you from and where you want to go, the website will tell you if you need a VISA for the visit.
One thing that I found interesting is that it also give some ranking, for example:
It turned out that if you are holding an US passport, you can go to most countries (168) without VISA. But a Japanese passport holder can meet largest number of people without a VISA (4 247 Millions).