Nicholas Courtney
Rather more sad is this particular section, as this is an obituary for one of my favourite Doctor Who actors ever (excepting The Doctor himself, obviously!).
The Brigadier was one of my favourite Doctor Who characters (beside The Doctor, naturally) and it with great sadness that we learnt of his passing on Tuesday 22nd February 2011 having suffered from a short illness.
Last seen in a Doctor Who TV programme in 2008 (The Sarah Jane Adventure's "Enemy of The Bane") Nicholas reprised the character of The Brigadier for us for the last time.