PDFpen 4.5.2

If you work much with PDF files, you may find that Preview isn’t quite powerful enough for your needs. While Preview, especially in 10.6, includes many annotation features (circles, lines, comments, etc.), that’s about the extent of its powers—you can’t easily insert an image into an existing PDF, for example, nor can you modify the text within that PDF.

SmileOnMyMac’s PDFpen not only marks up PDFs, but it makes short work of inserting images and even modifying, to some degree, the text within a PDF. It’s also got one very unexpected feature, especially in a program with a reasonable $50 price tag.