Trying hard not to feel old, I distinctly remember the joy I felt when Windows 2000 was released and gave Notepad users Ctrl-S as the keyboard shortcut for saving files (and don't forget the status bar with line numbers, too). I now feel a similar sense of joy as I sit here quickly taking screenshots using Paint (I've not had a chance to install anything better yet) on my Vista laptop - I can select an area and select Image ... Crop! No more fiddling in the corner of the white background thing to try to select the mock-crop thing while attempting not to resize the image accidentally!
That's going on my list of "insignificant to most but geeks will love it" reasons to install Vista.