Active@ File Recovery: Reliable and Affordable, but for Windows Only
Active@ File Recovery Standard is one of the more effective and affordable sector-based file recovery utilities on the market. At only about $35, it's considerably cheaper than R-Studio Data Recovery, though it lacks that product's support for non-Windows file systems. However, like R-Studio, it will deal with RAID volumes.
Active@ File Recovery is easy to use and offers both a quick scan mode for simple undelete operations, and sector-based "super" scan that will pull up virtually everything that's ever been written to a partition, or the entire disk if the partition structure is wonky. The interface is a bit technical in its language, but so is the task you're trying to perform. Still, it's not as easy for beginners as Piriform's free Recuva.
The $45 Professional version of Active@ File Recovery--the best bargain--comes with a partition recovery utility. That's a nice feature to have, because sometimes by simply restoring a partition you can get your OS back or recover files using standard copy methods. Like the Standard version, it installs under Windows only, so you'll need to attach the drives you'll be recovering data from to a working system. The $100 Enterprise version comes with a boot disk so you can work directly on a system with a bad drive.
I've used Active@ File Recovery several times to good effect: It recovered all possible data. The demo is fully functional with the exception that you can pull off files of only 64KB or less in size. That's enough for many word processing documents, but forget photos and video.