Cool screenshotting tool

I have long looked for the ideal tool to perform screenshots. While I have used the PrtScn button religiously in the past, I was always dismayed at the inflexibility of it — only capture 1 image at a time, only copy it to the clipboard, and thats it.
My ideal screenshot tool would have the following requirements:

• Ability to capture the screen, window, or a specific area
• Hotkeys to selectively choose the capture to do
• Automatically save the images to a folder
• Lightweight and easy to use
• Free

I finally came across a tool called Lightscreen (http://lightscreen.sourceforge.net/) that meets all of my requirements