At different ages, I have liked different books. When I was a child I liked more of Chandamama and other fantasy books. I always recommend that people should cultivate a reading habit first. This is more important than what books you read.
As for my all-time favourite book, I loved reading Buddhist Records of the Western World by traveller Si Yu Ki and translated by Samuel Beal. I also liked Ten Thousand Miles Without a Cloud by Sun Shuyun and Elisabeth Bumiller’s May You Be The Mother Of A Hundred Sons. They are all beautiful pieces of work.