Once again PhotoRec has been able to save files from a corrupt FAT USB drive. The application scans the partition, looking for known files (based on the file magic) and then restores those files. The files are not named as they were though, so there is still some manual work left, but the recovery works pretty well:

PhotoRec 6.12, Data Recovery Utility, May 2011
Christophe GRENIER 
http://www.cgsecurity.org

Disk /dev/sdc1 - 1000 GB / 931 GiB (RO) - WD My Book
     Partition                  Start        End    Size in sectors
     No partition             0   0  1 121600 253 63 1953520002 [Whole disk]


Pass 1 - Reading sector  464342462/1953520002, 10738 files found
Elapsed time 2h46m01s - Estimated time to completion 8h52m25
jpg: 7429 recovered
txt: 961 recovered
mp3: 558 recovered
tx?: 373 recovered
riff: 297 recovered
gif: 218 recovered
exe: 151 recovered
ifo: 126 recovered
mpg: 91 recovered
pdf: 83 recovered
others: 451 recovered

In Gentoo, you can find the package as part of app-admin/testdisk. To recover the files, I ran the following command:

$ photorec /log /d /path/to/recovery/dest /dev/sdc1

While skimming through the recovered files, I found a few ones that I deleted a long time ago but apparently never got overwritten (the data, that is). Scary to see how easy such recovery is... Makes me remember that, if you really want to delete files in a less recoverable manner, you can use shred for that.

And for those out there yelling to backup this data - you're absolutely correct, but no. I backup my systems and important files daily, but this disk contained (mainly) raw picture images and videorecordings. The manipulated, finished images and recordings are backed up (or at least on a disk and somewhere online), but the raw images and recordings are often too much to introduce a backup for, and if I would really lost them, I wouldn't shed a tear (nor panic).