There is a lot of options in Uttarakhand and Himachal Pradesh depends on your budget...but if you have an average budget then then you should try Malana(H.P.), kalga, kullu, Rishikesh, Chopta and many more
I will say Leh. Most beautiful place among all the places I have been to till now.
Last June I was in Leh and that's perfect timing to visit Leh.
And if you are planning Leh, then don't miss out Pangog Tso and Tso Moriri lakes. Breathtaking views. Hope it helps. Thanks.