Photo Source Via Web Designer Depot, also check out more information there.
Xerox 8010 Star (released in 1981)

Apple Lisa Office System 1 (released in 1983)

VisiCorp Visi On (released in 1984)

Mac OS System 1.0 (released in 1984)

Amiga Workbench 1.0 (released in 1985)

Windows 1.0x (released in 1985)

GEM (released in 1985)

IRIX 3 (released in 1986, first release 1984)

GEOS (released in 1986)

Windows 2.0x (released in 1987)

OS/2 1.x (released in 1988)

NeXTSTEP / OPENSTEP 1.0 (released in 1989)

OS/2 1.20 (released in 1989)

Windows 3.0 (released in 1990)

Amiga Workbench 2.04 (released in 1991)

Mac OS System 7 (released in 1991)

Windows 3.1 (released in 1992)

OS/2 2.0 (released in 1992)

Windows 95 (released in 1995)

OS/2 Warp 4 (released in 1996)

Mac OS System 8 (released in 1997)

Windows 98 (released in 1998)

KDE 1.0 (released in 1998)

BeOs 4.5 (released in 1999)

GNOME 1.0 (released in 1999)

Mac OS X (released in 2001)

Windows XP (released in 2001)

KDE 3 (released in 2002)

Windows Vista (released in 2007)

Mac OS X Leopard (released in 2007)

GNOME 2.24 (2008)

KDE (v4.0 Jan. 2008, v4.2 Mar. 2009)

awesome findings..
its funny to see how (almost) close each platform resembles to each other styles
Comment by dmf0 — April 20, 2009 @ 3:18 am
@dmf0
Yes, is also great to see the changes they made over years and years.
Comment by k — April 20, 2009 @ 11:51 am
good retrospective
Comment by Marko — November 20, 2011 @ 5:46 am