At RetroJunk I noticed a few posts in a topic where they letter graded each decade (or in one post, fragment a decade and give a certain portion better than the other). Now that the 2000's are complete, we can fairly grade that decade as well. Go as far back as you feel, even if it is before your time based on how much feel the pop culture from what you've read/heard/seen you enjoy.

I will work backwards.

00's: D
90's: B
80's: A-
70's: C+
60's: B+
50's: A
40's: C
30's: D+
20's: A

00's: C
90's: B+
80's: A
70's: A
60's: A
50's: B
40's: C
30's: C
20's: C

00's: D
90's: B-
80's: B
70's: A
60's: A
50's: A -
40's: C+
30's: C
20's: D

http://www.cracked.com/article/18355_the-top-10-decades-century-how-2000s-compared/ - The Top 10 Decades of the Century.

tl;dr: the 00's came 7th. The 40's came 1st - "But when you get down to it, any decade that features a bullet entering Hitler's head is a great decade."

00's: C - It has it's ups and downs to it, but I didn't think it was bad until towards the end.
90's: B - My childhood and the start of my teen years.  Hated the whole philosophy of the 90's, but it came out with great music.
80's: B - I was born in 85, so personally the 80's were a dream and the only things I know directly are kid shows.  However, I am a huge fan of GI Joe, so take that for its worth.
70's: A- - IMO, best of Rock and Roll came from that era.  I also smoke pot, and from what I have been told by my friend's parents, it was a lot easier to get. 
60's: A - A lot changed.  See it as my parents generation along with the 1950's.
50's: B- - I do like the conservative values, however I didn't like the racism.
40's: A+ - Honestly, if it wasn't for the WWII soldiers, we would all be speaking German.
30's: F - Recession
20's: B - Same with the 90's.

00's: D    If it weren't for the very first few years, I would give this decade an F!
90's: B+  My generation  8)
80's: B    Good enough but too much neon
70's: A-    Great music. I came into existance...
60's: B+    Radical changes happened
50's: C+    More low key yet too conservative
40's: B-    People dressed well
30's: B+  Not as glamourous
20's: A  I'm into glam so it's my favorite decade

2000's : C  culturally speaking regarding fads, fashion, music, events things that happened I would say it wasn't that great. However, on the personal side for me it was memorable decade. Especially from 2005 to 2009, '05 and '06 being my favorite years.
1990's : B- 
1980's : B+ 
1970's : A- 
1960's : C+ 
1950's : B+
1940's : C+
1930's : C-
1920's : D...maybe even an F.

00s  worst in music since the 70s and my adult life.... D
90s  depressing decade for me but nice music .... B
80s  bittersweet memories and the music.. the toys ... A ++++
70s  born here so not much to say - the music generally bores me.... C
60s  best pop rock ever... A +
50s  i picture this as black n white but the innocence n music are gone forever... A
40s  dads decade so. ...  A