If you followed this hint to create a Recent Items stack in the 10.5 Dock, you know that by default it shows or lists five items.
Now, if you're like me, you'll think it looks silly with a row of three on the top and only two on the bottom. To change it so that there are six items listed, go to the Terminal and type this:
defaults write com.apple.recentitems ABC -dict MaxAmount nn
Replace ABC with either Applications or Documents, and replace nn with an even number. Your stack (and the Recent Items menu) should now have an even number of entries.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20080319215158929