It all depends upon the interest of the traveller. Being Indians, I think, we have unlimited options to go on a holiday. Numerous beaches, hills and mountains, religious places, lakes and river banks, monuments, desert and forts and much more. Tourists can plan according to the season also. Thus, it's very difficult to name a few spots when India has so much to offer. Still, let me name a few: Puri, Puducherry, Kashmir, Goa, Amritsar and so on.
Ooty is a good holiday spot. I really enjoyed my previous trip to Ooty and wish to visit again. I also wrote an article 'Queen of Hill Station - The Nilgiris' in the article section. Please do visit my experience.