My two favorite things to do at Amazon is find e-book deals for my kindle and search for future releases in the Science Fiction & Fantasy section. I often come across books I've never heard of before. They're also usually the first to display new book covers. I visit Amazon several times a week and spend about 30 - 45 minutes browsing there each time.
I'm a Pinterest addict. It's the most distracting website ever created. And it's not just images of great art, pretty nails, and hot guys. It's also books. Lots of books. New cover reveals, DIY bookshelf ideas, fan art, quotes, unique bookends, and plenty more. You can even follow blogger reviews and publishers like Tor have Pinterest accounts as well. I spend more time on Pinterest than any other site.
Here's something you may not know about me..I buy more comics than I do kindle books. And the best place to get them is at Comixology.com. Just like with my e-books, I have more single issue comics than I can keep up with. I used to order subscriptions through the mail until I discovered that I could download their app and read directly from my kindle. I visit twice a week to see what's new, check out the freebies, and see what's on sale.
I first joined Goodreads in 2010 and while I'm not as active as I used to be, it's still a site that I visit frequently. I like to see what my friends are currently reading and check out their reviews. This helps when I'm making a decision on what to buy and occasionally when I'm having trouble deciding what to read next. This is also the site where I met the majority of my reading and blogging buddies. Goodreads has some issues, but it's still one of my favorite sites to visit.