So I finally got around to taking screenshots of my Powerbook G4's operating system, 10.5 "Leopard".
Click on the thumbnails to see the screenshot.

This is the default desktop. Plus a folder and a mounted drive.

The pinstripes present in previous versions have now been completely eradicated. The dock now has a 3D appearance, oh and reflections too!
The icons in the sidebar are now organized into collapsible groups. Apple also tries to sell you on their iDisk service by placing an icon for it prominently in the sidebar.

Like previous versions, the Finder can show you files in list, icon, or column mode. However, 10.5 adds this thing called "Coverflow" mode (which is in a basic sense a ripped-off idea from Windows XP nearly 6 years prior).

CoverFlow view displays gigantic previews that fly about in 3D as you scroll through them. You can drag these previews around as if they were icons as well.
Some file types, such as Quicktime Video, can play straight from this view.

It looks really cool, but I can't see where this is useful except for folders filled with photos and screenshots.

Here's yet another new feature. Place a folder in the dock, click on it, and WOOHOO! Up pops the files in a fan as shown, or in a grid if there are alot of files.
This feature is called "Stacks", and is apparently so intuitive Apple had to include a full-page document about them.

The unfortunate part is, this replaces the functionality of the menu such folders would open in previous versions. You cannot scroll through what's in there, nor can you open subfolders in stacks.

Multiple desktops are not new, but Apple brings them to the Mac in style.

"Spaces" as it's called, once turned on, will let you switch between desktops and open applications in each. The desktops can be previewed at once (as shown here), and you can even drag stuff between desktops (also shown here).

A whole bunch of bundled applications.