After more than 20 years of doing creative work on the Mac it has finally hit me that the productivity thing i would *kill for* is to have an "Open Windows" section in every save dialogue.
@helvetica Mark me down as another vote for Default Folder X. When a dialog box is open, just hover over any Finder window (even ones hidden behind the dialog or other windows) and click. Or you can use the DFX menu it adds to the window but that's less fun.