Make 10.6's List Stacks Look Like Grid Stacks
If you use Stacks in Grid mode in OS X 10.6, and you've read this hint, then you know you navigate into (and out of) folders in Grid mode Stacks using the keyboard. If you use List mode Stacks, there's no need for these techniques, because folders are opened automatically when you mouse over them. (If you're using the keyboard, you'll need to press the Right Arrow to expand the currently-selected folder.)
But if you prefer the Grid mode's method not opening folders unless commanded, you might like today's hint, courtesy of Mac OS X Hints reader arcticmac. After implementing today's hint, when you open a List mode Stack in Snow Leopard, it will look like a vertical version of a Grid mode Stack.
Instead of having folders that open in slide-out folders, as in the left-hand side of the above image, folders won't expand until you click the mouse (or press Return) with a folder highlighted. When you do open a folder, its contents will replace the current folder's contents, which is how Grid-mode Stacks work, too; a small arrow at the top will let you navigate back up to the parent folder (or you can press Command-Up Arrow).
(If you're wondering, this hint coexists nicely with this recent tip that explains how to always see a mouseover highlight effect in Snow Leopard's Stacks.)
To make this change on your Snow Leopard machine, open Terminal (in Applications -> Utilities) and enter these two commands, pressing Return after each one.
defaults write com.apple.dock use-new-list-stack -bool YES
After the Dock restarts, you'll see the new-look List mode Stacks. To return things to the default style, repeat the above two commands, but change YES to NO in the first command.