X-Men 122, page 19 (Volume 1)

This is the infamous graffiti page where Terry Austin inked in just about everyone who was a part of the Marvel Bullpen in the late 1970s.

Update posted on 1 June 2009:
During the Comic Art Convention on 31 May, Artemis (aka Artemaria) pointed out something of that I was not aware. Above the bed mattress at the bottom of the larger panel page is a newspaper. The headline reads "Abel strikes out again". Terry Austin inked in this zinger against Jack Abel. According to Artemis, Austin and Abel had a simmering disagreement that played out in the pages of the titles that the two were inking at the time in the late 1970s. Can anyone else point out other examples?