Definitely skim this thread from the beginning (if you haven't been following it). Lots of good info scattered throughout. However, for the short-form, I'd recommend ..

.. the Criterion laserdisc for the Kubrick-supervised transfer ..
http://originaltrilogy.com/forum/topic.cfm/Cinerama-70mm-2001-preservation-Is-it-possible/post/632583/#TopicPost632583 (Page 1 this thread)
.. with this releases caveat (ouch!) ..
http://originaltrilogy.com/forum/topic.cfm/Cinerama-70mm-2001-preservation-Is-it-possible/post/746946/#TopicPost746946 (Page 4 this thread)

.. the MGM DVD (which is supposed to come with a booklet) for it's awesome widescreen (letterbox) motion menus ..
http://originaltrilogy.com/forum/topic.cfm/Cinerama-70mm-2001-preservation-Is-it-possible/post/643160/#TopicPost643160 (Page 3 this thread) (note the referenced DVDBeaver's 2001 comparative-releases review with lots of eye-opening pictures)

.. and the Blu-ray for it's general clean-up & superior resolution.