Who's your favourite Dr Watson? Martin Freeman or Jude Law? Lucy Liu or Edward Hardwicke? It's so hard to choose, so spare a thought for poor Sherlock Holmes - faced with so many Watsons old and new, what will he do? Who's too techno-garish? Who's too teddy-bearish? Who's maybe too pretty? Who's in the wrong city? Who's the right Watson in Holmes's own view? And is Sherlock's Watson the Watson for you?