Rated 5 out of 5 stars
Was looking for something like this which is very simple and copied the grabbed area to the clipboard (an absolute necessity surely) and this meets my requirements.
I had tried and liked Shooter https://addons.mozilla.org/en-US/firefox/addon/13485 and Abduction! https://addons.mozilla.org/en-US/firefox/addon/3408 but Snapper is simply perfection.
Thanks for the positive feedback. I hope version 2.1 will be even more helpful than before. :-)