Stiefmo, I haven't heard most of those albums. Frankly, I've never even heard of some of those bands. I want to play along though, so I made my own little list. I'm not going with 20 though. Rather these are my 15 "Essential" Metal Albums of the past decade. Also, I don't really listen to punk, so this is all metal. I call this list...
There Will Be Whales15.
The Call of the Wretched Sea - Ahab (2006)

I promised whales, so you're gonna damn well get some fucking whales. Most of this album's lyrics are copied verbatim from
Moby Dick. Ahab's style is funeral doom, which I don't normally enjoy. This is awesome though. The band actually sounds like they're inside the belly of a whale under the fucking sea.
Listen to: The Sermon. It isn't on youtube though, so try something like
The Hunt14.
The Mantle - Agalloch (2002)

Any Agalloch album is worth getting, but this one is my favourite. This is the definitive rainy-day-cabin-in-the-woods album, but outside of that it's pretty good too

Listen to:
...And The Great Cold Death Of The Earth13.
Hangman's Hymn - Sigh (2007)

Sigh is...different. They call it black metal but this mix of crazy Japanese laughing/singing is pure madness. Hilarious too. Probably the funniest album of the decade.
Listen to:
Inked In Blood12.
Two Hunters - Wolves in the Throne Room (2007)

Black metal that doesn't sound like black metal. The band are all about agriculture and the environment, though I'm not sure their lyrics are intelligible to the average Joe.
Listen to:
Cleansing.
If you want to listen only to one song please let this be it. Turn up the speakers, close your eyes and listen to the first 4:40 minutes *uninterrupted*. After that, it's up to you. Best to brace yourself when the thunder rolls...
11.
Dopethrone - Electric Wizard (2000)

Crunchy! I love the hell out of this stoner metal album. I can only imagine the heights it would reach if I smoked weed. If you ignore that
Black Sabbath are still around, I'd say this sounds like a modern Sabbath album -- slow and heavy.
Listen to:
Funeralopolis10.
Lateralus - Tool (2001)

Tool, incredibly talented, but sometimes incredibly pretentious. I love em anyway. Lateralus is their best album of the naughties.
Listen to:
Schism. Seriously though, everyone should already know this song and its music video.
09.
To the Nameless Dead - Primordial (2007)

Primordial is a band that deserves to be heard more. They make music that comes from the heart and you can hear their pride in their country speak through the lyrics. I think their front man has one of the better voices in the business. It's a raspy voice like the lead of
Disturbed, just much better.
Listen to:
Empire Falls08.
From Mars to Sirius - Gojira (2005)

Whales muthafucka! These Frenchies rock. From Mars to Sirius is a concept album about how humanity must do something to save the Earth before it is too late. Along the way a guy flies through space looking for flying whales.
Listen to:
Flying Whales. What? You expected something else?
07.
With Oden on Our Side - Amon Amarth (2006)

Amon Amarth have been around for years and yet I could never get into them. This album changes things. They still sing about Vikings, Norse mythology and pillaging, but despite its goofiness this album is a treat to listen to.
Listen to:
Valhall Awaits Me (and follow the lyrics on the right). Then tell me if it isn't one of the funnest metal songs you've ever heard.
06.
In the Absence of Truth - Isis (2006)

Most of Isis' loyal fans will tell you that this is one of their weaker albums. I'm not one of their most loyal fans. In the Absence of Truth is their most ambitious album (it's inspired by Don Quixote along with several other things) and easily my favourite.
Listen to:
Dulcinea. (Links to a fan video, but a good one).
05.
Traced in Air - Cynic (2008)

Cynic broke up shortly after their epic 1993 album
Focus. Much to everyone's surprise they returned in 2008 and didn't suck. Far from it, they created the best album of the year and one of the best of the decade. Fans of Focus should be aware that this album is much more mellow though. The Death Metal influences are all but gone, it's mostly Prog Metal now. The slightly robotic vocoder voice may take some getting used to, but I think it's an asset to this group.
Listen to:
Integral BirthBonus: My only youtube video is a mashup of
Nunc Stans and
2001: A Space Odyssey. I think it came out alright and the comments I have are flattering. Care to give your friend Ed some views?

:
http://www.youtube.com/watch?v=dtG1OjpkCWY04.
Leviathan - Mastodon (2004)

Thought you saw the last of the whales? You fool! Leviathan is a concept album based around
Moby Dick (yes, another one). I've long considered this my favourite album by the massive force that is Mastodon, that is until I started making this list...
Listen to:
Blood and Thunder. Awful, awful video for a great song.
Also, this:

03.
Crack the Skye - Mastodon (2009)

I've come to the conclusion that Crack the Skye is Mastodon's best album. The whole thing is tight, there's not a single filler track on this record. Depending on your take, the album can be about Rasputin and worm holes or about the drummer's sister who committed suicide.
Listen to:
The Last Baron. One of the best songs the band has ever created.
I'd guess they would say we could set this world ablaze. Yes, you could say that. The Last Baron is the most
addictive song I've ever heard.
02.
Ghost Reveries - Opeth (2005)

Opeth. There isn't another band like them. It's a testament to their greatness that people who can't stand the death voice still adore this band. They got me back into listening to metal after I had given up for several years and they still haven't been usurped in my heart.
Listen to:
Ghost of Perdition01.
Blackwater Park - Opeth (2001)

More Opeth. I adore the way they shift heavy death metal segments to soft, beautiful ones sung with a clean voice. These shifts from heavy to soft and back again happen several times in most Opeth songs often at unpredictable times. The lead is one of the very few death metal singers who actually has a lovely clean singing voice and doesn't use the death growl to mask his inadequacies.
Listen to:
The Drapery Falls. A great example of the music the band makes. The lyrics start quiet and revert to that tone several times. In between...well, you'll have to listen.
Runners up: Anything else from Opeth, Mastodon, Agalloch, Isis, Tool and Primordial. A few
Neurosis albums too.
There. My kudos and sincere thanks if anyone actually reads this thing. It only took my around 2 hours to do.