(an individual or a group):
Aaron Koblin
Andrew Bell
Ben Fry
CASA - The Bartlett Center Advanced Spatial Analysis
Casey Reas
Catalogtree
Conditionaldesign
Design I/O
Fathom
Flight404
Field
Jonathan Harris
Kyle McDonald
Golan Levin
Google Data Arts Team
Jer Thorp
Local Project
LUST
Mark Hansen
Martin Wattenberg
Manuel Lima
Marius Watz
Moritz Stefaner
MIT SENSEable City Lab
Nathalie Miebach
Nervous System
Nicholas Felton
onformative
Ryoji Ikeda
Scott Murray
Scott Snibbe
Sosolimited
Wes Grubbs
Zach Lieberman

(an archive):
Flowingdata.com
Generative-gestaltung.de
Informationisbeautiful.net
Visualizing.org

(a book):
Beautiful Visualization / Noah Iliinsky, Julie Steele (2010)
Data Flow / Sven Ehmann (2009)
Data Flow2 / Robert Klanten, Sven Ehmann, Nicolas Bourquin (2010)
Semiology of Graphics / Jacques Bertin (2010)
The Visual Miscellaneum / David McCandless (2009)
Visual Complexity / Manuel Lima (2011)