I would also suggest starting with Nine, though I watched them wildly out of order with a mix of Nine and Ten (seasons 1 and 2) and only started a straight watch with Martha. (Whom I love. Dearly. A lot. So much so that I really prefer Martha and Donna to Rose and have trouble watching the Rose eps, even though that's the only way to get to some brilliant eps. ["The Empty Child/The Doctor Dances", the game show one, "Dalek"...])