Nice design, I actually like the green too..
A couple of pointers, however..
- Forum Home Alignment (see screenshot) - Fix available here.
- Category Strips - Look out of place, need a black border around them.
- Design isn't Centered - More space on the left than there is on the right, a little design flaw. Have an equal amount of space on the right using padding making the layout centered.. It'll look much better.
- Postbit - A lot of work needs done here.. Shrink the username size, and the alignment with the thread tools looks rather off. I'm fairly sure you're aware of this one already though.