Most applications on the Mac, but not all, use a small dialog box when performing saves. If you want the bigger dialog box that has the Finder-like interface that allows you to easily navigate directories, you have to remember to push the little arrow next to the file name. This isn't a very good interface element, and it usually takes me a couple of seconds to remember how to get the bigger save dialog. As it turns out, you can set a preference so that the bigger save dialog is always used as default. If you like the smaller dialog, you can also use this preference to make sure that the small save dialog is used by default.

To set this preference, you need to open a terminal window (found in Applications -> Utilities). Then type the following command:

defaults write -g NSNavPanelExpandedStateForSaveMode -bool TRUE

After that, you will always be shown the larger dialog box when saving documents. If you want to always get the smaller dialog, change the TRUE in the command to be FALSE.