MattyK -
Unfortunately, the menubar is supposed to be translucent, not opauqe.
ceezy3000 -
You shouldn't have had to download anything to make your menubar opaque.
Go to System Preferences > Desktop & Screen Saver and un-check (or check) the Translucent Menu Bar option and you can change it there.
Provided you had a graphics card that supported it being there in the first place...which I presume you did.
For example, my G5 tower w/ 64mb ram doesn't even support the translucent option so I never had to worry about it.