I have a brick I would turn into a Kindle but cant afford the shipping...
Seriously I think the WorldWalker is right...one easy (and fairly brain-dead) way of sorting out what your reader likes best is to go to Project Gutenberg and downloading various versions of something you like, try them out on your ereader and see which one plays well with others. Yeah they all say that they do PDF, etc but then reality comes crashing down and you either need a jewelers loupe or a billboard to read it (for example). When you find a format you like, then the options in Calibre will make more sense *and* you can determine if your reader doesn't read a certain kind or Calibre is doing a dodgy time of translating the format. Yes I love Calibre too but its not perfect.