gtx 960 or rx 480

Solution
Seeing as you are from India the current prices there are
GTX950 2gb- $200
GTX960 2gb- $230
RX480 4gb - $310
Since you will only be playing at 720p then either the 950 or 960 will easily max out games.RX480 is overpriced so don't buy that.
Other option is wait for RX470 4gb which will launch in next month and should be $250 in India.
960 will be more than enough for 720p, but i'd get the rx 480. You should buy the best you can. If you buy a poop, then you will want to upgrade later on, and probably spend more money. The RX 480 can handle games at 1080p, it's pretty much a 970 - 980.

Also the 480 kicks ass right now. Switching to team red for graphics cards 😛
 
Seeing as you are from India the current prices there are
GTX950 2gb- $200
GTX960 2gb- $230
RX480 4gb - $310
Since you will only be playing at 720p then either the 950 or 960 will easily max out games.RX480 is overpriced so don't buy that.
Other option is wait for RX470 4gb which will launch in next month and should be $250 in India.
 
Solution
A GTX 750Ti will do very well at 720p, with the 950 doing even better. If you're stuck between the 960 and Rx 480, go with the 960 purely because it's cheaper. Both of them are aimed at 1080p/light 1440p gaming so will deal with 720p amazingly. ~