Pig Iron listed ACTION 600 earlier, and I just ran across it again, and I think it was one of the last really memorable anniversary issues.

http://www.12comic.com/issue.jsp?id=1902270228079c89&cu=305

The predictable but pleasant romance between Superman and Wonder Woman by Byrne and Perez was a great open.

The Mignola story with Superman and Man-bat was also beautifully illustrated and atmospheric. From a point where Mignola had just reached his prime. Some really beautiful pages.