You probably know that if you double-click the icon at the bottom of a column, it will “right size” that column, so you can see the entire file name.

If you “Option-double-click” that icon, then all columns will be “right sized” to the maximum width necessary to display the longest item in the column.

If you want to change all of them press “Alt” while resizing. This will not only resize all columns at once, but also makes the new width the default setting for all windows.

In 10.5, Apple apparently felt these shortcuts were too hidden; there’s now a contextual menu hiding under the column resize widget, too. Just “control-click” on it, and three choices will appear:

Hopefully someday Apple will figure out how to get the “right size all columns” feature into the Finder, where it would be truly useful. Until then, though, at least it works in the Open and Save dialogs

Resize to fit column-view all columns in Finder is a post from: My MacOS X

In Snow Leopard you can now use the Tab key in any combination with the Shift, Control, Command, and Option keys. For example, you could change the Exposé All Windows activation keystroke to Option-Tab, which might make sense if you’re used to using Command-Tab to switch applications and want to have a similarly-assigned shortcut for Exposé.

• Open the Keyboard Shortcuts tab of the Keyboard System Preferences panel
• Select the Exposé & Spaces entry in the left-hand column
• Click on the All Windows entry below Exposé in the right-hand column.
• Double-click on the right-hand side of that entry
• And just press Option-Tab

and you’re done.

You can now use the Tab key in your user-defined shortcuts, which opens up a number of additional keyboard combinations.

Use Tab key in Snow Leopard keyboard shortcuts is a post from: My MacOS X

Click the top “split” button or press Command+D shortcut and now you’ve got your window split into two usable panes like so:
To collapse the window press Command+Shift+D

ALso, you can do multiple splits. Aside from general speed increase I think split pane in Terminal is my new favorite feature.

See the Terminal Splits Windows Movie:

Terminal Split Windows in Snow Leopard 10.6 is a post from: My MacOS X

While you hold down Cmd+Shift+4, you can also hit the:

• Spacebar to drag the selected capture region around the screen.
• Shift key to vertically or horizontally lock the capture region.
• Option key to expand or reduce the size of the region proportionately.

To make things even a bit more confusing, you can combine some of these keystrokes. Shift and the Space Bar together will allow a fixed-size region to be dragged in either a vertical or horizontal direction, depending on which direction you first move the mouse after pressing the keys. If you combine Shift and Option, then you can grow your region from the center, restricting either the vertical or horizontal size. As I said, it’s a bit confusing, so here’s a movie of the options in action.

Screen Capture in Snow Leopard is a post from: My MacOS X