While it's still no where near the powerful file explorer that the shareware alternative PathFinder is, the new and improved Finder does include several feature enhancements that—though they might seem superfluous and superficial at first glance—are actually pretty fantastic. Not only do new features like Cover Flow and Quick Look rank high on the snazzy scale, but they—along with a few other feature enhancements—make it that much easier to find the file you're looking for as quickly as you can. Gallery: Improved Finder
In general, most of the Finder enhancements are all about file transparency, helping you grasp not only what the file's name is, but also what lies inside the file. Icon previews, Quick Look, and Cover Flow literally showcase the file contents whenever possible. The Path Bar (though long overdue) shows you exactly where the file you're looking at is located.
One other great Finder feature that I was unable to try because I've just got the one Mac here is the screen sharing feature. Much like iChat's integrated screen sharing, Finder can also start screen sharing sessions. Unlike iChat's screen sharing (which works with any iChat buddy), Finder's screen sharing feature works with any Mac on your network. I've only got the one Mac at home so I couldn't try this out, but I'd imagine that since the other user has to be on your LAN, it should work like a charm.
If you've put the new Finder through the paces, let's hear your likes and dislikes in the comments.