A very good, and very long, article on how to improve the Finder is OS X, by John Siracusa. I need more time to properly digest it, but there’s some good stuff here.
The primary recommendation is the return of the “Spatial Finder”, meaning each object in the Finder appears in exactly one place—the same place that you last left it. His real-world example is a good one, the way that people can automatically find the light switch in the dark—muscle memory. The same can hold true in a computer interface. Witness OS 1-9.
Update: John Gruber of Daring Fireball offers his take on the above article. He’s had a few great articles on what is wrong with the Finder in OS X. Take a look.