See the "Login" and "Register" buttons up there? That bar? Rather use that.
While looking good is a critical issue for every site, being functional, easy to read, easy to navigate is even more important.
Big, huge header? Not needed. Plus, someone wandering into the site will spend some time before figuring what the site is about.
To be honest, the current site
layout is the best possible. On top general community navigation, on left informative sites and on right live server stats. Using an all-white with shades as a general theme would be best - especially if the community is meant to grow from just 1 game. Color variations for each game/community/large parts of the site. For example, TF2 would have red-ish theme, COD4 green and CSS blue or yellow. Just as an example. Buttons like that are a no-no. It's not a webcomic page, it's not a gallery, it's not a place where botchy beef buttons will fit in. In the end, I would say this: If this site is supposed to grow and adapt, it needs a simple, recognizable look or theme. Also, the changing header picture is nice. It could be made just out of ingame screenshots.
Also, get a proper logo to be used everywhere. It doesn't have to be a kickass comic awesome styled site name, it could be just Special Attack with a specific font.
I rest my case.
TL;DR: Don't focus too much on the looks. If site gets beefed up, it will be ugly and it will pretty much scare new players right off. Keep it nice and sleek.