Hm, this makes me wonder which version to read when I finally get around to it - the original one everybody around these parts read and based their opinion on, or the revised edition.
You have the same choice with the revisions done for some of the "Signature Edition" omnibuses (ie. minor date changes in "The Q Continuum"; but a bonus seven-paragraph bridging piece in "Pantheon"). "Duty, Honor, Redemption", which reprints the novelizations of ST II-IV, has had errors corrected, such as "McGivers" for "McGiver" and Sulu's promotion to captain is removed.
http://therinofandor.blogspot.com.au/2008/04/star-trek-signature-editions-if-i-ever.html
Somehow different versions make me queasy.
There's also: the Australian/UK editions of the novelization of TMP (several cool, bonus half-paragraphs explaining who Lori Ciana was); the MMPB omnibus collecting the "Starfleet: Year One" serial (new material and new characters); Kirk's as-screened death in the MMPB of "Generations" (the alternate/original death was in the hardcover); and the "Rihannsu saga" omnibus, "The Bloodwing Voyages", which corrects Diane Duane's original assumption that there was a second five year mission between TOS and TMP and corrects some dates and ranks.