Depends on what you want to experience..?
Is it an adventure ? or do you want to relax ? or just appreciate Indian history and culture...
Here are top 5 things you can do...
1) Adventurous and serene: Manali and Kasol
2) History and Culture: Udaipur and Jaipur
3) Wild and crazy: Jim Corbett
4) Relax: Haridwar and Rishikesh
5) Family trip: Dharmashala and Mcleodganj
Good luck.. FYI I have done 2,3,4.. And this december I will be covering 1 and 5 :)
If you want any detailed info do not hesitate to ask..
Cheers!