My vote goes to Bangalore new internation airport.
I have experience of going all of these airport personally, except hyderabad..
New bangalore airport is bit away from city, but it has spacious roads to reach there. Its new, and maintained top-class. I have seen few international airports, and i can say bangalore airport match those with quality and infrastructure.
Next comes Delhi. Its getting facelift also. So hope it will be much better.
Chennai and Bombay airport is okkishh. Even i heard bombay id going dome facelift, but i have not gone there recently.
Kolkatta is horrible.
I have not gone to hyderabad.