Season 6, Episode 4: "Weekend at Bobby's"
Whether or not you love "Weekend at Bobby's" likely depends on how much you like Bobby Singer. This Supernatural fan happens to adore him, so I will freely admit to being biased. But I maintain that this episode is a special one because it takes a break from Sam and Dean to follow Bobby through a typical day in his life. Since he's a hunter, a normal day for him involves burying an okami demon (and then burying it again when it comes back to life), doing research for the Winchesters, and dealing with the FBI when all the poor man really wants to do is eat some cobbler.