We recently acquired the Waves Restoration Noise Reduction Toolkit. This is a quality set of TDM plug-ins that competes well with the high-end system that has been considered "industry standard" for years. Four modules, "Click", "Crackle", "Hum" and "Noise" work individually or in any combination.
Since they are TDM plug-ins, they run in real time, thus giving the engineer the opportunity to evaluate the results quickly and efficiently. The "Noise" module takes care of most broadband problems and is particularly effective reducing common types of digital and analog hiss.
The other modules are more pertinent to vinyl restoration but the "Hum" module fixes recordings with various types of hum problems and the "Click" module will sometime remove digital clicks in one pass, thus saving redrawing waveforms by hand. By the way, if you are bringing audio tracks in that need noise reduction, please try and include a "sample" of the noise. In other words, a 3 or 4 second recording of the "noise floor" or background noise of the track without any of the musical content. Please do not cut the file tight to the music at the beginning of each track unless you are providing the noise sample as a separate track.