Captureka

Captureka is small and simple application for taking screen snapshots, annotating and creating comments on Windows system. While it's fully .NET written, it uses small amount of resources and due to gentle mix of hotkeys is extremely efficient.

Just press PrtScr, take a region snapshot, annotate with lines (L key), rectangles(R) and copy example to email (Ctrl+C) or save (Ctrl+S). Or use provided toolbars, just what suits your needs.