Diskeeper Lite doesn't work out-of-the-box in Vista; it complains about not having access to Terminal Services. After installing and uninstalling Diskeeper Lite, Vista thinks that there's no longer a defragmenter registered! Ay caramba! Another problem to fix later.
Vista's built-in defragmenter defrag.exe is mute (no status, no progress bar) so I have no idea when I can shut down my computer after I've started a defragmenting job. I found another free disk defragmenter program Auslogics Disk Defrag.