There's no particular reason why the files should be corrupt. It would need extreme circumstances for the HDD data to be damaged. Even moderate magnetic fields should not affect the drive encased in steel. The fact that the documents were made in older software versions should not affect the outcome.
The doc files will be mostly text. You could open some of them with Notepad to see the contents. There will be a lot of non-printing information together with a section of the actual text. The actual text may have some odd characters mixed in, for example where there is a new paragraph. If all text is garbled then you have serious corruption. If you have 10GB of files, you would need some form of automation to recover as many documents as possible (their unformatted text only).
Excel and jpeg are encoded files so you cannot do much with them if they are corrupted. Jpegs for example need the header. I've found jpegs particularly difficult to recover once deleted. If you have run out of recovery programs to try I can't see what else you could do. By recovery I don't mean "undelete", I mean programs that are designed to work with intact, specific format, corrupt files.
Hopefully someone else will have better ideas.
Edit: When looking for recovery programs, google strings like "repair xls" "repair word" "repair jpg" (all with no quotes).
Edited by Nanobyte, 24 November 2012 - 11:45 PM.