Many first posters will ask there question, not entirely sure how SE style works. I think most first posters think it's a forum style, and there is no follow up. If a user is posting a question on SP.SE, or even any SE site, they usually create their account for that one reason, to ask a single question. A lot of the times the question is valid and hasn't been asked before, but the great answers that get posted never seem to reach to accepted answer status.
Here's my suggestion to that. I was thinking it may be interesting to have a bounty-style first-post approach. Make every first-post a bounty style, where in 5 days the most upvoted post will win the 'accepted answer'. This can be completely overidden by the first poster if he/she so chooses. This will allow the accepted answers to be more abundant, and SP.SE will have a more completed question:answer feel.
This will have an added benefit for regulars to welcome first posts. It will encompass a more helpful attitude for first time users.