What's your opinion, either in a pop cultural or world sense? In other words, any year where there's a noticeable difference between the feel of the one before it and the one after it. From the '80s to now, I'd go with: 1981, 1983, 1986, 1991, 1997, 1999, 2001, and 2004.

I feel the biggest 'change/or transition' years of recent years were 1990/1991, 1993 and to a lesser extent '94, 1995, 1996/1997 and 1999/2000.

Can't comment on the 80s years, but I'd imagine 1986 was a big year with such events as Chernobyl, and of course '89 with the Berlin Wall, pre-Grunge like Sonic Youth storming the scene.etc.

1991, 1994, 1997, 1999, 2001, 2003

1981-The year the '70s finally stopped, and the bottom fell out of disco.
1983-I think spring 1983 was the beginning of the "real '80s", with Michael Jackson and the British new wave invasion.
1986-The year new wave stopped being a cultural force, Gorbachev talked with Reagan, hair metal got big, alt rock and hip-hop started to get big, etc.
1991-The '90s started and the late '80s ended...there was a slow gradual change from 1986 to 1991.
1994-A slight change, grunge went slightly over the hill and alot of the outlandish early '90s things went out. Gangsta rap came in.
1996-The first Y things started.
1998-The year Y2K started and "Y" culture really started.
2001-The year Y2K finally ended.
2003-Spring 2003 with 50 Cent and emo began the "real '00s"

How do you guys keep track of this stuff?  I can tell you years when my life was in transition.  But I have no clue what year anything else transitioned!  :D

1983, 1986, 1991, 1994, 1997, 2001

I think that every has some changes, and brings out something new, but generally speaking here are the years that I noticed changes:

-1981: Beginning of new wave, Reagan inaugurated
-1983: Beginning of 80's pop (Michael Jackson, Madonna, Cindy Lauper, etc.)
-1985: Hair Metal bands and soft rock became big
-1987: Rap became maintstream (Run D.M.C., Fat Boys, Beastie Boys, etc.)
-1989: Late 80's/early 90's rap and r&b blend, Simpsons premier, end of Cold War, neon colors came in, Bush Sr. inaugurated
-1991: Grunge started when Nirvana's Nevermind released, early 90's dance music became big
-1993: Gangsta rap came in, Clinton inaugurated
-1997: Glam rap became big with P. Diddy (known as Puff Daddy at the time), beginning of post-modernalism, premier of South Park
-1999: Teen pop became big with the debut of Britney Spears, Family Guy premiers, Y2K
-2001: 9/11, and Nu Metal became big, G.W. Bush inaugurated
-2003: 50 Cent debut, premier of OC, crunk music became big
-2005: Glam rap started to fade out, electronica came in (Gwen Stefani, The Gorillaz, etc.) as well as rap and r&b blend, American Dad premiers, new pope, rainbow and earth-tone colors came in

From a UK perspective . . .

1979 - Disco, Punk and New Wave were battling it out

1981 - The breakthrough of New Wave and New Romantics

1986 - The S/A/W era starts

1991 - Indie and Grunge makes it way to mainstream via help from Nirvana