Couple of additions....
Songwriters: Ryan Adams has to be in the conversation, given that every album he released in his solo career came in the '00s.
Artist: Jay-Z has to be in the discussion, if not towards the top of the list. Kanye doesn't go anywhere without him. Released this decade: The Dynasty (2000), Unplugged (2001), The Blueprint (2001), The Blueprint 2 (2002), The Blueprint 2.1 (2003), The Black Album (2003), Collision Course (2004), Kingdom Come (2006), American Gangster (2007) - not to mention the countless unofficial mashup releases and appearances on other albums/songs.
Rick Rubin, Marc Ronson, Danger Mouse, and Brian Eno should also be in the discussion, thinking along the lines of producers.