Having recently gotten into digital reading I've gone around and looked into places to legitimately get free ebooks. Most will also distribute them as .pdf in addition to .epub files. Since many of these librarys cover the classics, there will be overlap between them.
I've also found places to pirate todays bestsellers, buy obviously I can't post that. However even on just
one of these sites there is a staggering amount to look through. Certainly more than more than enough to occupy yourself with for quite a while.
Of course, if anyone knows of other such places, please do share.