Plenty of free e-books in Mobipocket format show up fine on Kindle.
Being at home on a rainy day, but wanting to read some new novel that just came out, you can have it in seconds. This concept (not hobbled by DRM) is pretty damned liberating.
Granted the PDF converter seems to have some trouble with graphics PDF's, but for books the converter works very well.
Use Mobipocket software to convert PDFs to that format so you can read them on Kindle.
A revolutionary portable reader that wirelessly downloads books, newspapers, magazines and blogs to a crisp, high-resolution electronic paper display that looks and reads like real paper, even in bright sunlight.