What is best site for downloading Ebooks?

I was wondering what site would be the best to download epub or pdf ebooks for my Iphone/Ibooks. Just wondering if there's a website like demonoid where I can find ebooks and not get viruses on my laptop.

I've been looking for these books:
By Light Alone - Adam Roberts
Our Tragic Universe - Scarlett Thomson
Legend - Marie Lu
Blood Red Road - Moira Young
Ashes, Ashes - Jo Treggiari
The Barcode Tattoo - Suzanne Weyn
How I Live Now - Meg Rosoff
Once - Anna Carey

Added (1). And not Piratebay!

Amazon is Great. You can get a kindle app for your phone or tablet or pc or mac.

Wow, it might be difficult to get all the above books.
Here is a list of sites for free eBook download. More than 30 sites are listed and don't worry about the virus.
http://www.ebook-converter.org/free-ebook-download-sites-list.html

Hope you find the books you are looking for.

Itunes via ipad or Iphoe.that's the best way mate.