It's a little depressing that nearly 150 years after Origin of Species revolutionized the natural sciences, there are still hundreds of millions of people, if not billions, who remain virulently opposed to Darwin's findings. But in fact, Darwin's legacy could not be more secure, with his theories of natural selection and survival of the fittest virtually unchallenged (and really, unchallengable) by any serious academics. The best that Creationists and neo-Creationists can do is try and promote dishonest pseudo-science like Intelligent Design.
So on this, Origin's sesquicentennial (try saying that five times fast), check out this interesting post at Evolving Thoughts, for some discussion of Darwin's influence on modern biology. Is our understanding of evolution a sine qua non without Darwin? Or would others have done the same work eventually?
(h/t The Panda's Thumb)