6. One of the Novelizations
Much like how the cook book is for the Whovian Chefs, this is for all the Whovians who are avid readers. Even if you aren't an avid reader, I still suggest you find one that sounds interesting and pick it up. The books are important to have because they tell stories we might never actually see on the small screen. There have been adaptations in to the show such as Paul Cornell's novel
Human Nature, but by and large the novels remain separate. The novels range in writers and Doctors, so there's something for everyone. It's also really good for when you want to go on a new adventure with The Doctor during a mid season break or waiting for a new season. There's even a novel where
The Doctor encounters vikings, which means you can find all different kinds of adventures. If my argument hasn't swayed you to read, there's also the audio book versions.