For myself I think, if you don't have to say something useful in that situation, don't say anything at all.
Instead I think it's best to let someone, who knows him and being in tough competition, say a few words.
And Larry Page posted on Google+:
Larry Page - 2:47 AM (edited) - Public
I am very, very sad to hear the news about Steve. He was a great man with incredible achievements and amazing brilliance. He always seemed to be able to say in very few words what you actually should have been thinking before you thought it. His focus on the user experience above all else has always been an inspiration to me. He was very kind to reach out to me as I became CEO of Google and spend time offering his advice and knowledge even though he was not at all well. My thoughts and Google's are with his family and the whole Apple family.[via Google+ Larry Page]