Yeah, I like black background. Roguelike classic. If somebody disagrees, give him a choice.
On the other hand, I find it very confusing to see where one post ends and another starts. It looks like this:
POST #1
--------
SIGNATURE #1
HEADER #2
--------
POST #2
Try adding something like a big horizontal bar between sig #1 and header #2, and have a different background color for sigs and headers, so that we don't confuse them with posts. Most forums I have seen (OK I have only checked phpBB and Chaosforge) also have different colors for each second post.
And I think we will need a spoiler tag.