Because some of your forums are hidden from guests I can't really coment on forum structure...
- In my opinion that banner really doesn't do the forum any justice. The skin is lovely then theres that banner. I suggest you make/request a new one

- The images used next to posts(the little boxes) don't match. They are the wrong colour and stand out too much

- The posting buttons look really poor quality for some reason. Ditto with the markers.
- Please change your rules from an image to plain text. Its annoying that you can't quote it. Besides people with screen reader will not be able to 'read' them

- The skins boarder images do not reach the top or bottom of my screen, thus it looks like they cut off

I hope some of that helps you =)
Edit: I used the winking emoticon four times XD