Window Clippings 2.0

[DigeratiPrime]

Window Clippings is a powerful yet unobtrusive screen capture tool. It is designed to produce the highest quality screenshots with the least amount of effort.

Window Clippings 2.0 was recently released and includes many new features and improvements. It is free to use but a license is required to unlock some of the more advanced features.

http://www.windowclippings.com/

Window Clippings precisely captures the transparency (alpha channel) of a window, including the shadow:

Best screenshot tool IMO