Could be any of the following:

1. The one you shoot best with
2. The one gifted to you by someone you love - your father or wife
3. The one you admire and want to have but cannot afford (kind of like wanting a supermodel or actress as a mistress)

I know the best rifle in the world in my opinion. It is a single shot 22 lr with a side swinging block that belonged to my closest friend and childhood hunting buddy from about twenty five years ago. He left India never to return and I bought the rifle from his mother just before I moved to the USA. I don't have it with me, but it is a reminder of my boyhood and a fantastic one at that. I don't think there is a better rifle in the world!

Cheers.