I'm currently using paint.net to capture screenshots and comment on them in order to report any UI issues on (web application) forms, misspelings, fields missing etc. I was wondering if there's anything more sophisticated to do this job as paint programs aren't that flexible when a page requires lots of modifications.
I second the recommendation for SnagIt. I love the fact that it will allow you to create and edit screen shots and movies. It is great when putting together documentation and training materials. Just an all around useful tool.