When I set up my computers, work computers, or friends/family computers this is what I generally will install:
Some version of Microsoft Office (if they don't have it I'll install free Office viewers),
Acrobat reader,
WinZip,
McAfee VirusScan (not the best, but when it is free who's complaining),
Whatever their current email program is (Netscape Messenger, Outlook, Eudora, etc) since I refuse to teach them a new one,
And every single Windows update and more importantly Office updates since I know they will never update the computer again.
Everything else I install depends dramatically on the person.