All the above suggested softwares and tools are really great. You can also go for Mac Data Recovery software to undelete files on Mac OS X. This is great recovery software and recover and restore all deleted files only with few clicks of mouse.
Various files are fully supported by powerful data rescuer, such as documents, photos, music, videos, emails, archives and more. Portable devices like external drive, USB drive, SD card, memory card, digital camera, Music Player and many others are supported completely.