A little late (like the great man himself), but yes, indeed, the middle of three Dumbledore actors has died.
I actually feel quite sad about this. I really liked watching him act. Never saw him on the stage, but I can imagine it was worthwhile if his screen performances are anything to go by. He was Marlow in one of my favourite pieces of television, the Singing Detective and that would be enough for me, but I never saw him in anything I didn't enjoy. He had a trick of looking surprised by what had just happened which was very engaging.
An oddity of a movie. I quite enjoyed it (think Lock Stock or Snatch, but bleaker and not so slickly controlled). I felt the editing could have been kinder to the audience - it's fiercely complex - but it still held my attention.
Edit: Michael Gambom was excellent and quite a different character from the crime boss he played in 'the Cook the Thief his Wife and her Lover'