Media files organisation

I need a program(s) that can scan my pc and show me duplicate files. 
Preferably with info such as location and file size so I can glance and 
narrow down which are dupes I want or not.

secondly......

I'd like a piece of software that can again catalouge my media files,
mp3's 
and videos. playlist stuff, to be able to launch from that program and 
rename file names if possible. I have many diff mp3's of same song
different 
mix but don't reflect in current name file. I spent 2 hours yesterday 
looking through diff folders for dupes and diff versions of same song it
was 
starting to annpy me :s

Cheers