I was in Dhanaulti last year at the Apple orchard resort. It was good fun. You can check that orelse Guwahati will be good too. Guwahati has lot of good pubs and party places. if that is what you are looking for. If you just want to relax then Shimla, Jibhi, Barot, Bir all should be good too.
Different people different opinion.. there are so many options in North India manali... in Himachal
shimla.. in Himachal
dharamshala & McLeod ganj in Himachal
Dalhausi & Khajiair in Himachal
massuri in Uttrakhand nainital in Uttrakhand
& many more.. like Lansdowne, auli, kasauli, almora, ranikhet etc. manali is my personal choice....