[X4U] Comparing disks, recovering data

[Zane H. Healy]

While my dual boot utility disk project has been going well this weekend, I
discovered an extremely serious problem.  My 750GB Data HD is corrupt to the
point that not even DiskWarrior can repair it.

I went out Saturday and invested in a brand new 1TB HD and a Firewire
enclosure.  The 1TB HD now sits in the G5.  The good news is I had cloned
the 750GB disk on September 8th, so the problem is less than a month old.  I
have the cloned disk, as well as an older clone (I believe over a month
old).  The bad news is there has been a lot of thrashing going on with the
disk (it only has about 1GB free space), and I've put a lot of digital
photo's on it in the last month (while moving what data I could to the boot
drive).  As near as I can tell I was able to copy most files over to the new
1TB drive, BUT I appear to be missing about 5GB and several hundred files.

Are there any tools besides 'find . -print' and 'diff' that I can use to
compare the three HD's (month old 750GB clone, corrupt 750GB, and new 1TB)? 
I want to try to identify what files are missing from the 1TB HD.  

I right now have TechTool Pro trying to recover files, but it looks as if
that will take about another day and a half to run.  Regretably I had never
bothered to install TechTool Pro, and didn't have it protecting the drives. 
Even worse, I've not been backing up my photo archive like I should as due
to some other issues my NAS is in storage.

Zane