I hate the name that the Finder gives duplicate files, as it adds copy at the end of the name but before the extension. This makes renaming files a bit more of a pain. Rather than creating a name like my file copy.ext, I'd like it to be copy of my file.ext, so I can easily select the beginning and have copied files all sorted together.
The way to fix this is easy. Go to /System » Library » CoreServices » Finder.app, control-click on Finder.app, and select Show Package Contents from the pop-up menu. This will open up a new window with all the files inside the Finder. Be aware that you can mess up the Finder up by modifying these files.
Go to Contents » Resources » English.lproj » Localizable.strings, and edit it in your favorite editor (I used Smultron). Search for N4, and you'll find a line that looks like this:
"N4" = "^0 copy";
I changed mine to:
"N4" = "copy of ^0";
Save the file, restart the Finder (using Activity Monitor or Terminal), and you should find duplicated files are now named according to your preferred string.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070831153858475