different people find different place interesting such as spiritual one wil like char dham,there are many areas for sight seeing,such as delhi ,munbai,holiday s are also for rest from busy life.so it particularly depends on person to person.
If its beaches and sun n sand then its Goa/Kerala
if you are looking for mountains n stuff I suggest Kullu Manali, Dargeeling,Ooty , Dheradhun
If you are interested in the temples then Rajasthan,orisa and Gujarat