At 35 I can no longer say that Arthur C. Clarke is my favourite writer, but it's hard to think of another who had more of an influence on me. As well as the incredible eye- and mind-opening qualities of his stories (how many people predicted communications satellites AND pay-per-view porn... in the same story?), he was the first writer whose style I was ever aware of -- not just style in terms of putting words and sentences together, but in terms of putting a story together. He was also the first writer whose work I consciously critiqued, which is why I rarely read his work after my teens... but like so many other people, I will miss him.
Of all the tributes to him floating around, I think the most touching is a collection of them at Global Voices. What's unique about these is that they all originate from Sri Lanka, where Clarke spent most of his life (and, of course, the future home of the geostationary space elevator.)