den4b is a coding trooper. Had it not been for paypal I would have happily sent my monthly movie watching budget to him in donations. Yes, it is that awesome. den4b ReNamer plays well as a portable application!
http://www.den4b.com/downloads.php?project=ReNamer
http://www.den4b.com/wiki/ReNamer
but wait there’s more. den4b is responsive to well written, intelligent feature requests
http://www.den4b.com/forum/viewforum.php?id=3
I confess I did not find this utility myself but was recommend it by a friend. Word of mouth — den4b has plenty of it.
I have tried several dozene renaming utilities, some freeware others shareware. When I had found myself comparing them all to den4b ReNamer I stopped looking for alternatives seriously. Now and again a forum or article will suggest a renaming tool not yet known to me — for kicks I’ll try it. ReNamer continues to win.

insert, replace, strip, regex. masking/selection, validation
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PacalScript, userscripts, presets, library of other user scripts … the power flows well beyond ReNamers GUI. Create a list of rules in the stack and see real time preview — this makes learning the advanced features orders of magnitude simpler. Cleanup those files for the media center:

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Now if only manual editing could would allow the program to generate a set of rules… replace your existing mp3 renaming tool with this! I realize high praise is not the same as cash, but for now it is the best I can offer (as paypal is evil)
a fantastic interface option is being able to set the text in the two respective drag-n-drop panes… mwahaha
Seth Wisely said: den4b or nothing