MSODREW  Definitely suited my purposes quickly. The interface does need a bit of cleanup, and Save isn't bound to command + s, but in general I can do gain reduction and noise/hiss reduction in just a few clicks. Plus, its free. 5-stars.  
(Version 3.14)

MSODREW  Excellently made and concise app. Preference menu has everything you need and nothing you don't. Highly customizable... not any skins as, say, Growl would offer but the value in simplicity defeats this shortcoming.

Automatically can fetch artwork and lyrics and attach them to the song file. Also is very "work friendly" in the sense that it will never get in the way of your tasks at hand.

Can be setup to start automatically when iTunes is launched.

And remember kids, this app is free as in beer... I'm impressed. 5 Stars!  
(Version 4.2)