GoodBooks.io - Largest curated collection of 8,500+ book recommendations.
Project Gutenberg - Project Gutenberg offers free ebooks to download.
Oku - Track your book lists and get recs from your friends
Rocket Reads - A simpler alternative to Goodreads
Bookicious - Find the best new book to read with books collections for makers, founders and entrepreneurs.
Glose for Mobile - A social reader for ebooks, now on Android