Hi,
I suppose this thing depends upon the preference of the traveler. I mean North India has lot to offer from Majestic Himalayas to splendid Desserts and Historical Destinations and it depends upon what type of trip you are interested in. Although in my opinion some of the best places in North India are Spiti Valley, Ladakh, Chitkul Village, Pushkar, Jaisalmer, Gulmarg. To be honest my personal favorite among these places is Chitkul Village, which is also the last village of India on Indo-Tibet Border. I mean visit to this place at anytime of the year would make you question the existence of Heaven. This place is not like other mainstream hill stations like Shimla, Manali, Mussorrie etc and you won't find any Shopping complexes, Mall Roads or Typical Family crowd on the streets. Away from civilization Chitkul is best for those who want to experience the true sense of Peace and tranquility or maybe want some time off from their hectic lives. In case, you plan on visiting Chitkul you can go through my comprehensive blog on Chitkul. Here is the link for the same: https://www.wanderworms.com/chitkul-village-the-last-village-of-india/