I purchased Saft, a plug-in for the Safari web browser on Mac OS X, a while back, after using the demo version for a couple days. The two features I used immediately and loved were:
- Saving open windows and tabs across quits of Safari (normally Safari forgets all your open windows and tabs, and restarts at your home page)
- Saving a full page as a PDF (as opposed to doing a Save as PDF in the print dialog, which breaks a long page into multiple pages, with no control over where the breaks are)