As we've settled in with Snow Leopard, we've found many tiny improvements. Undoubtedly, even more will be discovered as time goes on, but for now here's another healthy serving of unexpected - but much appreciated - refinements.
iChat -- Snow Leopard makes file sharing in iChat easier and more dynamic, and expands the program's interface options.
- iChat displays a progress circle when you send an image to another party. The circle fills radially.
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- Choosing View > Always Show Recipient Bar puts a buddy's status message and color at the top of any iChat window. It can also be used to select among multiple open iChat logins you have to send a message to that buddy, or to select among multiple accounts you have registered in Address Book for that buddy.
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Screen Sharing -- Screen Sharing in Snow Leopard sees expanded security capabilities, improved support for multiple monitors, and enhanced help resources for diagnosing connection issues.
- Screen sharing in iChat can now be encrypted if both parties sharing a screen have MobileMe accounts and have enabled encryption (iChat > Preferences > Accounts > Security).
- On a multiple-monitor system where you're using screen sharing over iChat, dragging the tiny inset preview of your own screen to another monitor shifts the remote screen to that monitor.
- The Connection Doctor (Video > Connection Doctor) adds a Network Status item to the Show pop-up menu that explains what kind of router setup you have; this feature is useful for troubleshooting problems.
- Screen sharing now properly transfers all keyboard commands to the remote server. For example, the Command-Tab application switcher switches applications only on the remote system's screen.
- Screen sharing also improves its notification when a connection is lost. Instead of a small dialog, the word "Reconnecting" appears with a startup-style spinner in large type across the window.
Networking -- Along with some tiny interface enhancements, Snow Leopard improves networking capabilities by extending Back to My Mac support across user accounts.
- It's a small point, but the icons for servers on the network (via Bonjour) that show miniature versions of the specific model in question are much prettier in Snow Leopard.
- Back to My Mac supports multiple users on the same computer. We had never encountered this, but only a single account in Leopard could have Back to My Mac enabled, regardless of whether Fast User Switching was turned on or off. Apple notes in a support document  that Snow Leopard allows each user to have separate Back to My Mac usage. (This limitation didn't keep MobileMe from working for multiple users on a single computer.)
Option-Click Tricks -- Option-clicking on things in Mac OS X has, in the past, often revealed additional menus or options. In Snow Leopard, pressing Option reveals even more.
- Option-clicking the Volume icon in the menu bar displays a list of sound input and output devices. Choose one to switch to it; it's much easier than using the Sound preference pane. Also, hold Shift and click the icon to set the system volume, which is separate from the general output volume.
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- Option-click the Bluetooth icon in the menu bar to view a few additional items in the Bluetooth menu. Specifically, it enables you to open three utility applications: Bluetooth Explorer, Bluetooth Diagnostic Utility, and PacketLogger. These are likely of interest primarily to experts, but if you're having troubles with Bluetooth, the Bluetooth Diagnostic Utility in particular may be useful.
- Option-click the Sync icon in the menu bar to display a menu showing each available sync service and when it was last synced. Other new items in that menu include commands to Reset Sync Services entirely and to open the iSync and Sync Diagnostics utilities.
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- Option-click the Battery icon in the menu bar to show the battery's current condition - Normal is good. Other messages might read Replace Soon, Replace Now, Check Battery, or Service Battery. Choosing the message opens a Mac Help document with more information; an Apple support note  also provides more detail, while this article  at Pocket-lint has great troubleshooting advice.
- Instead of pressing just the Space bar to enter Quick Look, press Option-Space bar to display the selected document in full-screen Quick Look, expanding the preview and hiding everything else that would otherwise remain visible.
Odds and Ends -- Snow Leopard seems to have an endless number of tiny tweaks up its sleeve, and here are a few final morsels.
- System Profiler (found in /Applications/Utilities, or by choosing Apple menu > About This Mac, and clicking More Info) offers a new File menu item: Speak Serial Number. Unfortunately, in our testing, the default voice speaks the serial number rather quickly, and changing the selected voice in the Speech system preference pane didn't slow it down.
- In Expose, when your mouse pointer is over a window thumbnail, press the Space bar to expand it (press again to return it to its minimized size).
- This will interest only programmers, but Quick Look now applies syntax highlighting for source code files in at least some programming languages.
- If the Trash contains locked files, emptying the Trash displays a new dialog that gives you the option to delete all the unlocked files, rather than telling you to repeat the action with the Option key held down to delete everything.
- In the Icon view in a Finder window, if any filenames overlap, the names in the background turn gray. It's a nice tweak to avoid the solid block of black that happens when lots of items are stacked on top of each other.
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Keep Us Posted -- While the majority of tiny refinements have most likely been found, as users continue to plumb the depths of Snow Leopard more are bound to be unearthed. If you stumble across any particularly useful, surprising, or interesting changes, let us know about them - and we'll do the same!