I would suggest go for A320 Type Rating since not many people opt for it-as yet. Indigo, Go air and possibly later in the year-Kingfisher might be a viable option.
Boeing 737-800 (NG) has too many people typerated on it, with too many NOCs issued for the same. However on the bright side 737 jobs seem to be in the bucket loads.
ATR- Has
no orders/deliveries from any indian airline for some time to come (I guess Kingfisher will get one later in the year). Not many jobs too.
I did my ATR rating six months ago and am still waiting for a response from any airline. 
Air India Regional came up with vacancies, but is usually all rigged. I wish I had done an A320/B737 Type Rating back then.