The guys at Web Designer Depot put together a list of screenshots from various Operating Systems dating back nearly 30 years. If you haven’t had a browse already ensure you do, otherwise have a skim of our selection below including the latest Windows 7 release.
Xerox 8010 Star (released in 1981)
Apple Lisa Office System 1 (released in 1983)
Windows 2.0x (released in 1987)
Mac OS System 8 (released in 1997)
Mac OS X Leopard (released in 2007)
GNOME 2.24 (2008)
Windows 7 Release Candidate 1