I guess this is annoying to some and not a big deal to others.  (“this” being the fact that Windows Vista IE/WE and file browser dialogs do not have an “up directory” button).  Besides just being weird it can be a hassle when you still work a lot on WinXP/Win2003 and are use to the convention of having an up button.  Of course MS allows you to use the “directory tree buttons” to easily navigate to a higher directory – which is pretty good, but not a complete solution in some cases.  If you click in the location area and start to type a new directory, there’s not an obvious way to restore the buttons (because now it’s just a text box containing the file path).  By the way, pressing Esc twice with focus on this text box does restore the buttons.  However, the thing I was interested in sharing was the ability to press Alt-Up Arrow and just go up a directory like normal.  So, the next time you notice the up button is missing just remember that Alt-Up Arrow in Vista does the same thing.