In comparison with other question and answer sites, I can kind of see how a question which doesn't have an accepted answer may be misleading to a user who found it via Google and isn't otherwise familiar with how the Stack Exchange engine works.
When there's an accepted answer, the check mark serves as a flag to indicate that. But when there's no accepted answer, there's really no indication either way. A new user may not know what an "accepted answer" is until he stumbles across one.
Up-voting/down-voting is another indicator, but in my experience there are many questions and answers which have no votes at all, if for no other reason than they're just not popular enough to receive any attention. Many times when we discuss how the engine works we unintentionally think in terms of the entire community acting upon a single question and set of answers. But a lot of the content doesn't get that kind of attention.
I would be in favor of some kind of visual indicator on the page which alludes to the fact that these answers have been submitted, but the person who asked the question hasn't "accepted" one of them. Granted, this will draw more attention to the fact that a lot of drive-by questions never get accepted answers, even if they're perfectly good answers and even if they actually solved the person's problem. But that's another story entirely.
As an example, the MSDN forums have separate sections for "answers" vs. "all replies." The way they approach it isn't entirely friendly and intuitive either (I had to do a double-take the first time I was there because content was listed twice), but it's an interesting presentation of the data. I'm no UX expert by any means, but it would certainly be interesting to see some ideas from the Stack Exchange team on presenting more explicit cues about the state of the answers for a given question, even if it's nothing more than a language change on existing page elements.