I have no idea how this design process thing works, so I'll just blurt out stuff until the ball gets rolling :)
This site is all about Blender, so it seems logical to me that the site would in some way be themed around that.
What reminds me of Blender?
The logo is of course made up of three colors:
Incidentally, these are similar to the colors of a Dutch flag, which is where Blender started.
In addition to the logo colors I tend to associate a dark gray with blender as well. Not too sure why.
Am I the only one who sees "Blender" when orange and this kind of gray are together?
As Blender's mascot since the beginning of (open source) time, Suzanne is a distinctly Blender icon. An easter egg that is recognized by blender users everywhere. For example, the Suzanne Awards is the one of the largest Blender competitions around. And perhaps that association with an award adds an extra reason to use Suzanne's image for something like a badge icon.
Meshes, geometry, "3D" things
Blender is a lot of things. Video editing, motion tracking, image manipulation, the list goes on. However it's most widely known for it's 3D modeling.
The basic building blocks of a 3D model are polygons made up of little vertices, edges, and faces. (triangles if you want the most basic of them all).
So as GiantCowFilms suggested, perhaps it might be interesting if these fundamental pieces of 3D were somehow referenced or incorporated in the design.
This site (like all SE sites), is more than just a support site. It has a little community too, and most of the blender community is all about creating art. So I (and others) feel it would be natural to make artistic imagery a part of the site, perhaps with a contest to regularly create new header art.
Here's a short list of other large Blender related sites, perhaps looking at some of them can help inspire (or perhaps serve as lessons in what not to do):
This list is not at all complete, there are many more blender sites out there.
After writing this, I couldn't help but try a few things.. Of course these are all just my random personal ideas and don't mean anything (I'm not the designer here ;).
Discussion and feedback is of course welcome!
Assuming SE doesn't want to use the blender logo (?), I attempted to come up with some kind Q&A + blender related logo/favicon thing. Though it pretty much just looks like the blender logo..
Small and in context:
Not enough "pop"? ;)
There are of course the Suzanne badges which I'll copy here just so everything is in one place:
And some flattened voting icons, since flat seems to be current "modern" (the ones in my original proposal were based off the old beta theme, with lots of shadows and gradients).
Make of this what you will, I look forward to seeing what the professionals do!