I have been with Flipkart with quite some time now (find posts on Flipkart on this site). But there have been other entrants in the market for online shopping and they are good.
With declining discounts on Flipkart (no dip in service quality) I like most online shoppers tried finding other online shopping sites offering discounts. There are many more online sellers for books and other items. One can always compare prices at sites like MySmartPrice, IndiaBookStore dot net or Isbn . net . in and also find discount coupons or codes at coupon offering sites.
Of late I bought many books from uRead dot com. Service is good and fast: it is like the Flipkart of 2010. I still use Flipkart for online shopping, you can never ignore it.
Sites like Indiaplaza, Homeshop18, Infibeam are all okay but not as fast as uRead or Flipkart. It is good to do some online research and buy from various sellers if you have the time. Flipkart is the leader (and I am one of its original customers) but other entrants to market will be more open with discounts and offerings for obvious reasons.
So far I had no problems with uRead at all. Usually they delivered within 24 hours (Delhi).