2012-06-07:
Google Chrome
Notepad++
SSH Secure Shell
Python
Eclipse
Winamp
Xming
Filezilla
Foxit Reader
7zip
Dropbox
ImgBurn
SyncBack
TeXworks
An older version: (still shown to demonstrate the changes I've been through as a user)
Unlike Ubuntu, a fresh copy of Windows comes with absolutely nothing. So I made myself a little list of all the necessary components, as not to leave a computer I take care of without some of the essentials.
* Drivers: lookup the computer's model and search for the drivers. Some manufacturers maintain pages with all the necessary installations on them.
* Office: have a copy ready. OpenOffice is also a good option but I never ran it under Windows.
* 7zip - http://www.7zip.org
* IrfanView - http://www.irfanview.com/main_download_engl.htm
* Foxit Reader - http://www.foxitsoftware.com/downloads/index.php
* DivX - htp://www.divx.com
* Adobe Flash - http://get.adobe.com/flashplayer/
* BsPlayer - http://www.bsplayer.org/bsplayer-english/download.html