Many of Google's Web apps have been long on functionality but short on looks. Google Reader, the Web-based RSS reader, is a good example of this. Fortunately, Google Reader Mac OS X Snow Leopard + Delicious is a Safari extension that makes Reader look good.
Once installed, this extension makes Google Reader resemble a Snow Leopard application (like iTunes). The sidebar is that same faint blue, and the rest is white and gray. Additionally, dialog boxes are the same nearly-transparent black that we've come to expect from Snow Leopard.
This extension is simply a new set of clothes for Google Reader, so its functioning is unchanged. There, now doesn't that look better?