I am a diehard fan of flipkart. All ye guys at Flipkart, keep up the good work. The speed with which you deliver is not matched by any service provider in India.
I have tried Homeshop18 and Infibeam. Though homeshop18 is cheaper for some books, they take a long time to deliver. But worse than homeshop18 is infibeam (atleast that is what my friends also tell me)