Navigate folder structure in Open/Save File Dialog with keyboard? After hitting ⌘-O, how can I navigate my folders and select a file to open using only my keyboard? 

In particular, how can I get the focus into the folder list? (From there I can use arrows or start typing the first letters of the desired file/folder.)

In some programs I can rely on hitting TAB 5 times, but this isn't reliable and I figure there must be a better way.
System Prefences > Keyboard > Keyboard Shortcuts > Enable "Full Keyboard Access: All Controls", then you can use Tab to move between elements until your file list is highlighted, and use the arrows to select your file, in fact you should immediately be able to type a letter or use the keys as the default focus should be on the file list.