If you are like me and you think the Cocoa theme is butt-ugly and you prefer to use Alloy instead then you have probably noticed that the font rendering is all messed up on Leopard. This is because Java 5 now uses a different rendering engine, and that results in weird text drawing in both static and editable fields.
The fix is pretty simple fortunately. Just add apple.awt.graphics.UseQuartz=true to IDEAs properties. You can do this by opening IDEA from the Finder using 'Show Package Contents' and then opening the Info.plist file. There, add a new text entry to the Java.Properties dictionary with the above setting.
Looks much better :)