If you have recently deleted a file you actually want or if you noticed that a file has been removed from your computer by an uninstall of another program then the data recovery program best suited for your situation is simple Windows recovery software. This is assuming you are on a Windows based PC. If you are on a MAC or Linux driven computer you obviously need specialized software for those applications.
Most Windows data recovery tools will also accommodate some basic file recovery from USB flash drives and camera smart cards. They will not however do a good job with RAW camera files.