I'm surprised that Sigil (https://code.google.com/p/sigil/) is not in the list. If you want to develop your book directly in ePub format (as opposed to developing it in some other format and then converting) Sigil is the place to start. Else, you can use it for checking the last bits (TOC, cover, etc.) before publishing your book.
PS: I'm in no way affiliated with the Sigil development team, just a happy user.
I'm surprised that Sigil (https://code.google.com/p/sigil/) is not in the list. If you want to develop your book directly in ePub format (as opposed to developing it in some other format and then converting) Sigil is the place to start. Else, you can use it for checking the last bits (TOC, cover, etc.) before publishing your book.
PS: I'm in no way affiliated with the Sigil development team, just a happy user.