I too have downloaded a lot of e-books, but really have a hard time with managing them. Several years ago I decided to subscribe to Packt's e-book service, at

I too have downloaded a lot of e-books, but really have a hard time with managing them. Several years ago I decided to subscribe to Packt's e-book service, at $10/mo it's a pretty safe investment to try out. I honestly found the fact that it manages the book for you (favorites, folders, keeps the right page amongst multiple devices, history, etc) was pretty much worth the price. After the first year I upgraded to SafariBooksOnline, which is quite a bit pricier, but has all of the Packt, Orieley, and more books. There are still a lot of books that suck, or aren't what you're looking for, but you do get to look at the whole thing before investing any more money or time into it.