I read White Tiger because it was recommended to me. It is good.
I didn't like The Namesake as much, it was too slow and boring...just like the movie. Read the book first but the movie was a bit better for me.
Sister of my Heart is good and read it a long time ago and always wanted a movie adaptation.
Q&A is awesome! I loved it. Very different from Slumdog Millionaire. Loved it! Also read Vikas Swarup's other book, The Six Suspects. Loved it.
Other Desi authors and books I love are...
If you liked Sister of My Heart, try Amulya Malladi's two books - Mango Season & Breath of Fresh Air, loved both. Breath of Fresh Air has some of the Bhopal incidents in there, very heart warming. I love how it's written with each one of the character's point of view. Mango Season is hilarious, it's about a South Indian who is going back home to India, a country she once loves and now is annoyed with everything, that's what happens when you leave home for a while.
Or brainless fun books by Sonia Singh - Goddess for Hire, Bollywood Confidential, and Ghost Interrupted