Not bad! This is actually one of the best grayscale templates I've seen The header images and gradients are good. The background and the banners are also good.

I absolutely love your board descriptions. Very original and creative. Maybe you could use some sub-boards with some of the categories and kind of make it more tidy looking. Having too many boards on one page isn't too fun to go searching for.

The PM bar drop down should math the forum width. It completely exceeds it when you go and check your pms.

Perhaps add a bit of color in there with some staff colors and rank images.

If you could make all icons light colors in all of the icons and lighten the gray a bit, it would look more welcoming. Having just gray makes it a bit dull.

Other than that, great board!