I am wondering how useful the accept rate stat is. It seems to me that a stat that shows participation might be more useful. I doubt even on my best day I could be the one to give the accepted answer to one of Jon Skeet's questions (which are often more musings than questions). However there is no doubt that he gives back orders of magnitude to SO than he takes.
Now, in Jon Skeet's case the rep alone indicates participation, however there are many people who ask few questions but answer, or try to answer, many. And some people's questions simply have no answer -- they are looking for something that doesn't exist. So they may have asked 5 questions with only 2 having acceptable answers but they may have 50 answers and 20 are accepted. Such a person is clearly participating and giving more than they are taking but their questions are labeled with the unflattering "40% accept rate".