I do have a lot of free classics that I've downloaded from here and places like
Feedbooks. Personally, I haven't filled my Kindle in advance with books to read. I have a ton of free samples, but I don't feel the need to buy a book unless I want to read it right now. Getting a book is so convenient that unless I'm collecting for collecting's sake I don't see a big benefit to it. I might buy a few books in advance this week because I'm leaving the country next week on a trip and I'm not sure how good my Internet access will be while I'm away but here at home, I have Whispernet everywhere I am in my day-to-day life.