Why? There's already enough.
My suggestions: Keep a similar theme. The dark theme suits the site well.
Keep most of the main features of the site, such as the Main Page featuring, well, featured songs, and the forums, obviously.
The focus of the site is creating and sharing songs, so keeping it simple to access to composer is key, maybe even putting it on the banner of the site (simply click and it opens). Having easier access to shared songs will help so much too. Filtering options, like filtering out featured songs in the search. Speaking of the search option, make it default search for songs, rather than the Songs in the News Section (why is that the default search filter?), as this always yields 0 results.
Browse should be more prominent as well. It should include a few tabs, "Recent Songs" being the most important, and allow for filtering directly in the browsing, as it already does.
The IRC chat and Groups are rarely used. These seem irrelevant at this point. I'd suggest removing irrelevant tabs.
Looking at the site, a lot of the features I'm suggesting are already used in some fashion, so my most important tip would be keeping most of the site as similar as possible.