Folders Deleted For Unknown Reason - Best Recovery Software?

I've been working on renaming all my music for the past few weeks using a program called Tag&Rename. I have over 350 Gbs of music so it's been quite the undertaking but I've made a fair bit of progress. Until all of a sudden in the middle of renaming some albums today I was shocked to find that all my albums from A through S were just...not there anymore. All my work had just vanished for no apparent reason. I had just deleted a redundant music folder when this happened and thought that maybe I had somehow deleted more than I asked for but there's no trace of the folders anywhere not even in the recycle bin. I did a complete search of my computer looking for Bob Dylan just to see if I had somehow put all the files in some other folder by mistake but no luck. So I downloaded a bunch of free undelete software packages and scanned my hard drive and they couldn't even find the missing files. It's as if they just vanished. Is there any software out there that can help me in my search, or does anyone know what could have happened? I don't mind paying up to a hundred bucks if I can just get my lost work back. I obviously need a program that will maintain my original folder structure since renaming files and folders and changing my folder structure is all I've been doing. I have most of the music backed up on another drive but it's all mistagged and disorganized. I really don't want to start all over again.