Accepting answers is completely optional.
The question owner is not required to accept an answer to their question. We view accepting an answer as a simple social convention, a little informal “thank you” between the asker and answerer, a virtual tip o’ the hat to that person whose response, as the question owner, you personally found the most helpful.
That doesn’t mean the community will agree with your choice. But as the question owner, it is your choice to make.
The default sort order is “votes” for a reason. Normally, the best answer will automatically float to the top through community voting. This is important because we expect a lot of our question askers to be drive-bys, programmers who ask a single question, get the answer they need (or don’t), and are never seen again. This is intentional and by design.
From http://blog.stackoverflow.com/2008/11/why-cant-i-accept-my-own-answer
Basically, voting is extremely important. Accepting answer is great, but we shouldn't be pushing users to do it if they're not ready.
For myself, I haven't yet encountered answers to my questions that I consider fully answering the question. Accepting an answer at this point would be premature, and would potentially discourage other answerers.
Keep in mind we have very few active users. We only went into public beta today! As we gain more users, we will gain more and better answers, and the number of accepted answers will go up accordingly.