I think the most famous district for temples is Mandi but Mandi is not the choice. I am of the view that Mandi is also known as CHOTI KASHI because there are many temples in Mandi. From your choices Kangra may be the right choice.Aim at Sky and You will Hit the Mountain Top.
I also thinks the same, because there are about 81 temples in Mandi. Some of the temples are world famous like- Tarna Devi Shikari Devi Bhootnath Naina Devi Maahunaag temple etc. For 81 famous temple Mandi is also known as Choti Kashi.Regards, Narender Sharma. Editor- Himachal Spider