Can pilotbob, Nate the great and anyone else who's Kindle isn't being detected run the following commands with the Kindle connected and post the output.
Code:
calibre-debug -c "from calibre.devices.scanner import DeviceScanner; s = DeviceScanner(); s.scan(); print repr(s.devices)"
prs500 info
prs500 df
prs500 books
@pilotbob, When you send to the device it looks at what formats the book is in. Calibre allows you to store multiple formats for the same books. Say you have a book and it has the following formats ebub, prc, and txt. When you send to the device the device driver will report what formats it supports in an ordered list. It goes down the list and the first match it find it sends that version. The Output selection on the upper right of the Window does not deal with sending to the device. It deals primarily with what format to save content downloaded from the internet (news, rss feeds) in.