Hey Rahul, I would recommend going to Vagamon & Varkala; lesser know beach places in Kerala. Ooty and places near by are too cliched now, also the weather won't be very comfortable as it will be Summer time.
With lush green tea estates and chilly weather, Munnar would be the perfect choice. However, one should away from the crowd of the main town and head to beautiful resorts around Munnar. Pondicherry would also be a good option for summers.