Clarke's collaboration with Stanley Kubrick on 2001: A Space Odyssey, I think, more than any other writer, has shaped our current vision of what the future might be, especially in the area of space travel. I wonder if Clarke felt it ironic that the year 2001 has come and gone, and we still do not have commercial space travel, a permanent space station with a mall and hotel, a permanent Moon base, manned probes to the outer planets, or Artificial Intelligence. Nor, due to the short-sightedness of our leaders, are we going to have any of those by 2010, either, except possibly commercial "space travel" in the same fashion you might have called paying the barnstormer to take you up in the back seat of his biplane after the air show "commercial air travel." On the other hand, HAL and his brothers Colossus, et. al., are good arguments why we might never WANT Artificial Intelligence, so Clarke might have helped prevent that development from coming about.
Clarke was a scientist by philosophy, a Distinguished Supporter of the British Humanist Association, and it has been noted in the press that he forbade any religious observance as part of his funeral. It is, therefore somewhat ironic that his short story most remembered by other writers I have seen is the undeniably elegant "The Nine BIllion Names of God," unless you consider the callous indifference of a God using humanity as nothing more than a count-down timer. Clarke was also the author of "The Star," a harshly anti-Christian piece many thought shocking. He was quoted as having said "The greatest tragedy in mankind's entire history may be the hijacking of morality by religion."
Clarke was made a Commander of the Most Excellent Order of the British Empire in 1989, and was knighted in 2000, among other honors. Clarke's writing won him Nebula and Hugo awards, and in 1986 he was named a Grand Master of the Science Fiction Writers of America.
When asked by Wired Magazine in 1993 what his epitath should be, he replied, "I've often quoted it, 'He never grew up; but he never stopped growing.'"
Clarke continued to work throughout his life. According to reports, he had finished reviewing the manuscript of The Last Theorem, co-written with Frederik Pohl, just days before his death.
One of the ongoing debates in SF these days is whether near-future hard SF is "dead" due to the fact that technological advancements are occurring and being adopted too fast for writers to keep up. I do not agree. This may be true of cellular phones, personal media players or personal computers, but not so much in other major fields. What have been the major developments of the last decade? "Hybrid" cars, super-jumbo commerical aircraft, miltary "stealth" technology, but that's about it. Given that, I feel that Clarke's works stand up very well and will continue to be classics. He will be missed.