In Mac OS X 10.5, if you select more than 10 files and then choose File » Get Info from the contextual menu, Finder automatically opens the Inspector, showing a summary of all 10 files.
In Snow Leopard, though, Finder opens the Get Info window for each item, quickly filling the entire screen on smaller displays. If you want the summary style Get Info window instead, hold down the Control key before pressing Command-I; this changes the Get Info menu item to Get Summary Info, and you'll see one summary Get Info window for your selected files.
[robg adds: Control-Command-I works in 10.4 and 10.5, too. I marked this one Snow Leopard only, though, because it's related to Snow Leopard's handling of move than 10 selected items with multiple Get Info windows. A brief history of Get Info and multiple selections:
10.3: Get Info displays a summary window for all selected files.
10.4 and 10.5: Get Info displays individual windows for each selection up to 10 total, unless you use Control-Command-I to view the summary window. With more than 10 files selected, you always get the summary window. The only way (that I know of) to see more than 10 individual Get Info windows is to select files in batches smaller than 10, then do Command-I on each batch.
10.6: Get Info displays individual windows for each selection, regardless of how many files are displayed. Use Control-Command-I if you want the summary window, regardless of the number of files in the selection.
The Snow Leopard implementation seems like it's the most flexible, but it does require some training time to remember to hold down Control and Command when you know you want the summary window.]
In 10.5, you could bring up the Get Info window (or Inspector) for a file you downloaded with Safari, and view the URL from where you downloaded it (in the More Info section), which was useful. However, you could not copy or select the URL, and had to retype it to visit that address.
Now, in 10.6 you can now drag-select across the URL field, making it easy to copy and paste -- or you can Control-click on the selection and select Open URL from the contextual menu.
In a Finder window using Icon view, including the Desktop, if the icon size is set to 64x64 or greater, .pdf, .key, and .ppt files will have forward and backward arrows overlaid when you mouse over their icons. Clicking these arrows allows you to page through the document one page at a time.
Previewing the document with Quick Look, viewing a different page, and then closing Quick Look changes the icon view preview to the new page. You can then continue to page through the document with the overlaid forward and backward buttons from the new location.
One caveat: previewing with Quick Look only updates the icon to the new page if you used the overlaid forward or backward buttons on the icon at least once before opening Quick Look.
Taking focus off the icon returns the icon preview to the first page of the document.
For a year or more, I've been having trouble with application icons frequently not copying when I copy a file from one folder to another in the Finder. I would get a generic icon on the copied file, and have to copy and paste the icon from the original to the copy. The problem persisted after I upgraded to Snow Leopard. I concluded that it was an incurable Finder bug -- no amount of system maintenance would fix it.
Then I found a little free app, Refresh Finder, that solved the problem (there are a few other apps that do the same thing). Rather than restarting the Finder, these apps just refresh the window, and the icons appear as they should on recently-copied files.
As it happens, this window refresh issue has been around for a long time; other manifestations include files moved or copied or downloaded to a folder not showing up. I guess I was just being dense, but I didn't connect the two (mis)behaviors. But they are, it seems, one and the same problem. Anyway, you can drag and drop the Refresh Finder app to the Finder's tool bar to have it handy in every window; just click on it whenever either of these window refresh problems occurs. For me, it is a simple and welcome solution to a vexing problem.
[robg adds: Macworld's Dan Frakes covered Refresh Finder as a Macworld Gems entry a couple years back. As Dan explains in his article, Refresh Finder is a front end to a relatively simple AppleScript:
tell application "Finder"
tell front window
update every item with necessity
If you're running Snow Leopard, create a new Service in Automator, set it to work in Finder (receives no input), and then add the Run AppleScript action to your Service. Save your Service, and you can then (using the Keyboard Shortcuts tab of the Keyboard System Preferences panel) assign it a keyboard shortcut. Now you can refresh a Finder window via the keyboard.]
Snow Leopard adds the ability to play audio files directly from a Finder window in Icon view (including your Desktop); 10.5 can play audio files in the Preview column when in Column view mode. Hover your cursor over the icon in Icon view, and a play/pause button will appear. As long as you do not change the selection in the Finder, the audio will continue to play even if you switch applications.
In Icon View, this integrates cleanly with Quick Look. You can press the Space Bar to open Quick Look on a playing audio file, and Quick Look will take over with no skips or jumps in the sound. Switching applications with Quick Look open still halts the audio, but another press of the Space Bar to hide Quick Look before going back to work will let you keep working to the music.
Unfortunately, Quick Look does not work as smoothly in Column View. Both the Preview column's player and Quick Look track their place in the file separately. Quick Look pauses the Preview column's player when it is opened and starts the audio from the beginning, but does not unpause in the same way when it is closed.
[robg adds: In 10.5, when previewing audio in column view, opening a Quick Look window would actually play the audio file twice, with no sync at all between the two.]
Quick Look has a hidden feature that is not enabled by default, and can only be enabled through Terminal. Essentially, when 'X-Ray mode' is turned on, Quick Looking a folder will show, in a way, the contents of the folder.
Instead of just seeing the regular folder icon in Quick Look, the folder icon will be semi-transparent, with previews of the folder's contents visible in the Quick Look window, as seen in the image at right. What's more, the preview images will rotate automatically, moving through each item in the folder (click the image to see a movie of the animation).
To turn this on, quit the Finder (using Activity Monitor, Terminal, etc.), then open Terminal and enter this command:
Relaunch the Finder, and enjoy the new folder X-Ray mode in Quick Look. If you ever want to disable it again, quit the Finder, then repeat the above Terminal command, but change the 1 to a 0.
[robg adds: The image and movie above are from my machine; I added them to make it more clear exactly how this feature works. While it's a nice visual effect, I'm not sure how really useful it may be. Update: Hint republished to note that it works in both 10.5 and 10.6.]
When navigating the Finder in column view in 10.6, the system now allows the use of Tab/Shift-Tab to go forwards and backwards in the folder hierarchy. Unlike (for me at least) 10.5, the arrow keys also work reliably for that now.
Another interesting tweak is that using Tab/Shift-Tab does not change the current working directory, so you can hit, for example, Shift-Tab three times, then hit Right Arrow once, and you'll be one folder deeper than you were when you started.
Here's an AppleScript that toggles the presence of the sidebar in all Finder windows. Toggle status is determined by that of the front window. In Tiger, it sets the sidebar to its minimum width; in Snow Leopard, it hides it completely. The script leaves the toolbar alone.
After hastily upgrading to Snow Leopard, I found myself without various tools I had grown used to. One such tool was the SCPlugin, which provided a contextual menu for many operations with Subversion repositories.
After reading that Finder contextual plugins are now no longer possible (in the Ars Technica Snow Leopard review), I gave up hope of an update being released. Services are seemingly the nearest equivalent. Fortunately, Automator now makes making your own services relatively easy. I confess to never having used Automator before today, so this may not be the best way, but it at least goes some way to restoring the functionality I lost.
These two workflows provide Update and Commit commands, which is all I find myself in desperate need of right now. To create both, launch Automator and select Service from the initial screen.