Good websites for buying books online

Normally when I buy books online I buy them from Indiaplaza. They have a decent collection and give discounts too. When I could not find a book with them, I turned for to try some other websites. One is flipkart. The other one is Scholars without Borders. I read their blog often and the website is maintained by an erudite group of people from JNU. The prices at SwB are very competitive. I realised after I had ordered from flipkart :(