I feel like what you are saying is true for mainstream music. However, there are still plenty of good musicians that don't get much radio play. It is popular music that sucks now, not so much all of the music within this century.

bob dylan - the times they are a-changin
bob marley - legend
drake - more life
fallout 3 ost
george harrison - all things must pass
john lennon - plastic ono band
lil b - i’m gay
lil wayne - dedication 2
marvin gaye - what’s going on
michael jackson - thriller
toro y moi - samantha
young thug - slime season 2

First of all, WOW! Was not expecting to find a HUGE MJ fan here but your list blew my mind. Even better, YES, Dangerous was his greatest musical achievement. Should have done better than it did had it only came out one year earlier (1990) before Nirvana'a Nevermind changed the music scene (1991) and knocked Dangerous off the charts. 

Anyway, before I posted my list I scrolled around to see if I'd find someone that places an MJ record at #1 haha.

This is tough, but I'll give it a try (also, gonna try to limit my choices by artist as my musical tastes are quite open-minded and to be honest...I only consider very few albums to be truly worthy of any list. Gonna just include one's that truly made an impact on me. Many artists nowadays are incapable of making great albums.) I LOVE many artists and a ***T-ton of songs, but very few albums. There are many albums that have just one or two MASTERFUL songs but I cannot include them for just two songs etc. So yeah...this is tough. 

1] DANGEROUS|Michael Jackson

2] ENIGMA|Love Sensuality Devotion: The Greatest Hits 

3] KATATONIA|The Fall of Hearts

4| OPETH| Blackwater Park

5] NIRVANA|Nevermind

6] ACE OF BASE| The Sign

7| ULVER| The Assasination of Julius Caesar

8| NIRVANA| In Utero

9] ENIGMA| MCMXC a.d.

10| DELERIUM| Karma

And yeah, greatest hits SHOULD count as the RIAA includes them in their top selling albums lists. For example: The Eagles' greatest hits is their best selling album and the 2nd best selling album of all-time.

Late to the party.
Anyways:

Everything from Rage Against The Machine.
Rage Against The Machine, Evil Empire, Battle of LA, Renegades.

Live albums from Daft Punk
Alive, Alive 2007

Phil Collins' hobby band from the seventies - Brand X.
Unorthodox Behaviour, Moroccan Roll

Two artists from Iceland:
Sigur Rós
Ágætis byrjun
&
Björk
Debut

Unfortunately I have not found any music from the latest decade that has become a favourite.