People are going to say Bangalore, but Bangalore today is pain in the ass to stay in.
It has all the problems that India already faces (density, unsanitary conditions, rising pollution) and outdoes almost all other big cities on commutes. Easily the worst traffic in the country.
It does have a great tech industry and weather though.
If I had to go back, I would go to Mumbai (Western Suburbs or South Bombay), because that's where I grew up. Also, the new metro and road projects have potential to solve transportation in India. (though completion is maybe 10 yrs away)
_______________
I personally, meant townships like Lavasa (or what it was intended to be. It became a holiday home / Indian cape cod instead).
A place where the city could be designed from ground up, and some of the common problems of every Indian city would be avoided by design.
They are much cleaner with better air and urban design. It legitimately feels like you are in a developed country.
Some photos:
https://image3.mouthshut.com/images/Restaurant/Photo/-66070_...
https://magnificentmaharashtra.files.wordpress.com/2015/01/g...
IMO, Nagpur would have been well positioned to become that, had it not had such terrible weather.
It has decent amenities, excellent educational institutions (IIIT, NIT, IIM, AIIMS), Good public transport (with the metro and new roads), a new SEZ, a new airport and doesn't have any other major negatives.
Gurgaon's cyber-city and Noida were other totally botched attempts at this. Terribly bloated, copied the worst aspects of American urban design and left zero opportunities for any organic growth of culture in the area.
I can see Goa with BITS's presence, the weather and cosmopolitan nature being well poised for such a development. However, unlike Nagpur I've yet to see any attempt being made to urbanize that region.
Navi Mumbai and Powai had a similar opportunities to build themselves from the ground up, but both have become more natural suburbs of Mumbai rather than entities in and of themselves.
________________