Dramatic licence - good or bad?

Here's a question. What do you all think about dramatic licence? Are you in the camp (as I used to be) who demand complete and total fidelity and adherence to the source novel, are you at the other extreme where you think anything goes or are you somewhere in between?

I, as stated, used to demand a rigid adherence to the source material and so was frequently annoyed, to some degree or other, by most Holmes dramatisations. Now I realise that this looks odd to anyone who knows me and also knows that the film that first got me interested in Holmes back in 1982 was Basil Rathbone's The Scarlet Claw. Anyone who has seen it will know how un-canonical it is.

Over time I have drifted from this strict position (but not too far). I still think that outrageous dramatic licence (which is more about a director/screenwriter's ego) should be discouraged but intelligent changes designed to suit the medium should be encouraged.

Please comment and let me know which adaptations of Holmes stories have pleased/irritated you the most