The TARDIS barrelling down the M4 chasing a taxicab.
Brilliant. Beats Morecambe and Wise, any day.
EDIT, 7:31 PM: The second greatest moment of Doctor Who: The Doctor on a Segway.
Seriously, folks, I haven't seen them all yet, but it's the funniest, most frantic, the most energetic and in many ways, the most touching of the twenty-first century Doctor Whos I've yet seen. (Tho' I've not seen the Sarah Jane episode yet.)
EDIT, 7:59 PM: And at the end, a preview of the new season (William Shakespeare! Daleks!) and of the Sarah Jane Smith series starting January 1st. It's a good time to be a Doctor fan.