Don’t you like the gnome-screenshot shadow effect and knapshot region feature?
Well, I like both effects, but unfortunately can’t have them both in one application. Moreover I don’t like to start such overkill applications like Gimp or stuff.
Since I’m an KDE user I do have the ‘region’ goody, and am missing the shadow effect. Now I’ve find out, that I can launch the gnome-screenshot with the KDE environment without any problems. It’s simple done by executing this in the command line:

gnome-screenshot --interactive

Unfortunately it’s not a standalone gnome application, and it’s part of something I don’t know. I just remember, that I’ve installed gedit (apt-get install gedit), which is an easy notepad alike editor, which I prefer. Maybe I’ve installed also something else, but I simply don’t remember anymore. But here’s my dpkg -l output of all my installed gnome binaries.

These two screenshots are showing the knapshot, taken with gnome-screensaver and vice versa.
One must have in mind, that adding a shadow to a window includes, that you’ve got to save it in a format, which can handle the alpha channel (transparency). Png is such a format, but jpg e.g. isn’t.

I’m using Kubuntu 8.10 (Intrepid Ibex) but it should work for all other common Distros like Fedora, Gentoo or SuSE and Debian of course, too.