Zero Assumption Recovery (ZAR) is the trial version of a commercial undelete tool - but don't let that put you off. While most of the competition place major restrictions on their trial builds, ZAR can recover up to 4 folders, and also includes a basic image recovery tool which works forever, no registration required.
Whatever mode you're using, the program supports a wide range of file systems: FAT16, FAT32, NTFS 1.2/ 3.0/ 3.1, ext2/3/4 and XFS. It supports NTFS compression, and ZAR can even try to reconstruct broken RAID 0, RAID1+0 and RAID 5 arrays, so there's a great deal of power here.
If you choose the full data recovery mode, then it's just a matter of selecting the drive with the missing files, and leaving ZAR to do its work. Which may take a while, because the program is exceptionally thorough, and inevitably that means it can also be slow. (Although you can tweak things by changing how the program handles bad sectors, and allocating more data to its read cache, for instance - check the full-sized screen grab to see how that works.)
Once the program has eventually finished, you're able to browse an Explorer-like tree of files and folders to try and locate your missing data. Or, alternatively, the built-in search tool will help you locate files by name, date or size, and you can then recover your missing data in a click or two.
Please note, the company also produce tools to create disk images, or recover email messages from corrupt mail databases (Outlook, Outlook Express and Thunderbird are supported). Find out more at the ZAR site.
It's not cheap, but Zero Assumption Recovery is a more powerful undelete tool that most. If other programs can't restore your lost files, give this one a try.