It takes a lot to impress me with screen capture program. I mean, I've always just relied on Alt-Prtscrn, or Paint Shop's capture tool.
Well, I stumbled across this one today and I must say... very impressive!!
http://blogs.geekdojo.net/brian/articles/Cropper.aspx
Side Note: Not really intended to make nifty Screenshots of a desktop though. Here's why, per the authors web site.
Cropper does not capture semi-transparent / layered windows. Since Cropper is itself a layered window, adding the ability to capture other layered windows causes the Cropper window to show in the screenshot. Cropper was originally designed to easily pull out parts of web pages for documentation or images out of vector graphic comps. Alternative capture methods are coming that will enable the capturing of full windows.