Disk Warrior or Data Rescue II?

Disk Warrior and Data Rescue are really two completely different utilities serving different needs. Disk Warrior is used to perform repairs to a damaged or corrupted hard drive directory. Data Rescue is used to restore files that have been deleted or lost because of disk directory damage.

If you need to recover data from a hard drive that was damaged or recover files you've deleted then you use a utility like Data Rescue. If you need to do directory repair you use Disk Warrior (or TechTool Pro.)

Have you tried repairing your external hard drive with Disk Utility? When you say the drive failed do you mean it is no longer functional? If that be the case then you will not be able to recover the data with software. To recover the data the drive must be functional and accessible.

try filesalvage from subrosasoft if the disc still mounts but your files are missing,free trial i think that just shows you what it can rescue reasonable cost depending on which version you go for(different versions for different file types).

http://www.subrosasoft.com/

also disk warrior is not yet ready for intel macs.