I have just discovered http://unxutils.sourceforge.net/ which, in addition to the various GNU utilities such as grep, diff, sed, etc., comes with pclip.exe and gclip.exe that output and input the clipboard to/from stdout and stdin respectively. This means you can chain a text processing utility in between, such as pclip | sed "s/string1/string2/g" | gclip.

Although I've never been a Unix user, I truly appreciate the power of chaining text processing comands like this, and might well convert my clipboard processors to stdin/stdout processors, and have the shortcut run a piped command chain like this.