I agree with TRshady on this one. A combination of both disciplines is by far the most powerful... albeit a little fiddly. A number of years ago me and a friend worked on an interface for a site called GamingKingdom that featured an interface with databased CSS definitions, thus allowing the site to have variable user-selected skins. Think Spoono on steroids.
Oh how I wish we'd saved the code as opposed to just the design..
