Greatest of the decade has to be MBDTF. Truly a remarkable distillation of late 2000s pop music, particularly Power and All of the Lights. I think what I like most about this album is that the main theme of the album (the excess and narcissism of celebrity) is briefly relaxed to give profound self-reflections. Compare in Power "f*** that, the world's ours" to "you got the power to let power go", in Monster with "I crossed the line", in Runaway with "I could never take the intimacy / and I know it did damage / 'cause the look in your eyes is killing me".
Other strong contenders:
Chuck Person - Chuck Person's Eccojams vol. 1 (2010)
Catalyst for the vaporwave scene; peaked before it even started. It's easy to forget that the sampling in this has strong noise undertones, consider Eccojam B2.
Death Grips - The Powers That B (2015)
Not my favorite DG album, but you can't deny that this is their most complete project. Disc 1 focuses on glitchy sampling while Disc 2 is practically hardcore punk rock.
Tyler the Creator - IGOR (2019)
At the beginning of the decade, I don't think people would've expected Tyler to make a heartfelt neo-soul record about a gay love triangle but here we are. This album is really neat compositionally because each song contains maybe like a single 1-3 second passage where the melody changes in really creative and pleasing ways. Also GONE GONE / THANK YOU is a masterpiece.
Some personal favorites:
Owl City - All Things Bright and Beautiful (2011)
It was super popular to hate on Owl City at the time (he was seen as a bargain brand Postal Service), but I think he deserves a re-evaluation. These songs are all well produced and incredibly catchy. Captures a sense of naive techno-optimism from that era.
The Caretaker - An Empty Bliss Beyond This World (2011)
It's like being in The Shining except nobody died yet, but they're about to.
Death Grips - Government Plates (2013)
I know this album gets maligned because of some of the shorter tracks, but to me they're really spooky because of how minimal they are.