A real frustration I found when using older versions of Acrobat to redistill a PDF was that I had to specify the page size each time. If you regularly create PDFs of different sizes and want to redistill them, this can be pretty disruptive to you. Acrobat 6.0, thankfully, fixes the problem.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.