See also: the Dvořák Symphony Cycle Survey, the Beethoven Piano Sonata Cycle Survey, the Bach Organ Cycle Survey, and the Bruckner Symphony Survey Cycle.
Update 19/01/2013: Colin Davis' second (first LSO) cycle is being re-issued and already available in Europe.
Update 12/01/2013: Abranavel's, Karajan and Bernstein's incomplete, and Ashkenazy's Stockholm cycle added. Links and images updated and Amazon-links internationalized. Ionarts's Choice cycles updated. Misdirecting links double-checked after initial posting.
Update 04/01/2013: Paavo Berglund's first cycle with the Bournemouth SO, long out of print, has been re-issued as a super-basement bargain by EMI. It's been included below, replacing the Royal Classics release.
Update 12/12/2012: Colin Davis' third cycle (on LSO Live) is out in a box and has been included below. His first cycle has been boxed by Decca, and has been added in place of the two Philips twofers. To keep the symmetry, Sixten Ehrling's Stockholm cycle (available on German Amazon and on HMV.co.jp) has been added.
Like the Beethoven Piano Sonata Cycle Survey, this is a mere "inventory" of what has been recorded and whether it is still available. Favorites are denoted with the "ionarts' choice" graphic.