When Apple said they were going to redesign the Finder, we though, oh, we've heard that before. But with Quick Look and Cover Flow, Leopard introduces the most significant upgrades to the Finder since the 10.1 to 10.2 transition. One of the most time-consuming aspects of using the finder is previewing files. If you're thumbing through a folder looking for a file you need, and the only way to identify the right file is by peeking into it, OS X can really slow you down, at least until Friday when Leopard arrives.

Quick Look is a system-wide technology that the Finder takes advantage of in order to give you fast previews of a file's content within the file system browser. Unlike thumbnail views, which were sloppily implemented and didn't actually work all the time on previous iterations of the OS, Quick Look actually supports all kinds of files, from movies to Keynote presentations and images. Plus, Quick is the name of the game, as anybody who has used Cover Flow on in iTunes will attest.

The other new feature we looked at this morning is Parental Controls, which Apple has amped up by adding to the Preferences window. Historically Apple has done pretty well by allowing parents to designate which applications children can run (and even which web sites they can visit), but with so many cool kid-oriented web sites popping up all the time, it's hard to keep up with the demand. Echoes of, "Hey Dad, can you unlock this web site for me?" can drive a parent bonkers, especially when it's happening five or six times each time your kid sits down to surf.

For the first time, Apple has implemented some content filtering in Safari. They've adapted the anti-spam filter from Apple Mail as a web content analyzer, and apparently it works well enough for blocking "no-no" sites on your kids' behalf. Of course, if you still want to totally lock down your kid's browser, Safari will still allow you to permit only those sites you've approved ahead of time.