The question of whether there will be a season 3 has been brought up a number of times on this site. Maybe the moderators could sticky this thread or one of the other threads regarding this topic so it can be easily found.
As of 12/06/2011 I have checked all the official Japanese websites connected to this anime series and there is still no word of any future productions.
If Gonzo (or some other company) did decide to produce more of the series I would like to see them start over with an alternate retelling as opposed to continuing on with the current series. The second season, while it had some good episodes, was difficult to watch having read the manga and knowing how much of the original story was changed. Don't get me wrong, I really do like the anime which is why I pre-ordered the limited edition bundle back in January but I couldn't help comparing it to the manga while I was watching it. If the series was continued into a 3rd season I would definitely watch that one too.
Post your thoughts on whether there should be a season 3 or an alternate retelling. Please include in your post if you have or have not read the manga. Hopefully the production company will see an international interest in the show and consider putting it back into production.