7 July 1919: birth of Jon Pertwee, the Third Doctor, star of the show from 1970 to 1974; the first Doctor I can remember, the gentleman wizard who spends a lot of his time on Earth. I'm in the middle of rewatching Pertwee's stories at the moment and actually liking them a bit more than I did last time round.
ii) broadcast anniversary
7 July 2009: broadcast of the second episode of Torchwood: Children of Earth, with Jack reassembling his exploded body, getting encased in concrete and then busted out by Ianto, while Gwen and Rhys head for London and the children chant, "We are coming tomorrow."