I was going to blog about what I think about the mixture of the "brushed metal" look and the more traditional Apple look in Mac OS X, but someone else already wrote everything I wanted to say: http://daringfireball.net/2004/10/brushedmetal.
The Finder is especially annoying in that it switches itself between brushed metal and plain-old-window depending on whether you show or hide the toolbar. With the Apple Human Interface Guidelines encouraging developers to look to the Finder as an example of correct UI design, it's not surprising that people can't agree on the appropriateness of the brushed-metal look or on many other aspects of how a "real Macintosh application" should work.
I don't understand why Apple wants its applications to look like a bunch of overpriced components for audiophiles.