In my opinion (and I’m fairly certain John agrees), Doctor Who is the greatest television show of all time. It has the capability of making any idea anyone has be cool no matter how stupid it seems on paper. There is no reason Agatha Christie fighting a giant bee, finding Satan in a black hole, or Vincent van Gogh fighting a parrot-bear should be good at all. It manages the perfect balance of campiness and absolute devotion to presenting any plot as true so that they can tell any story with a certain degree of seriousness. The Daleks are perfect as the ultimate bad guy because they encapsulate this idea. There is no reason a trashcan on wheels with a toilet plunger ans an egg beater sticking out of it should be intimidating, but they are presented as so terrifying and the show is so wacky already that the viewer actually buys it.
One of my favorite parts of Doctor Who is that a lot episodes can be boiled down to an episode of Scooby Doo. It presents a traditional supernatural or historical problem like vampires or nazis. Then towards the end, The Doctor pulls the proverbial rubber mask off and reveals everything to be aliens. Then, he and the gang hop in the Mystery Mobile TARDIS and moves on to the next adventure.