If you forget the T-Pain/Cher effect Auto-Tune is a highly useful and good sounding plug-in. I’ve been using the previous version for a few months now and it does add a certain something to a vocal that I haven’t found in other plug-ins. I use Melodyne too but they are different enough tools if vocals are very important to your music. Besides correction there is added sheen that I think you would associate more with a good pre-amp and mic. You can also nicely lower a vocal’s pitch with some formant settings and it sounds very interesting.
“This video, produced by Groove 3 Inc., is an overview of Auto-Tune 7’s new features, focusing especially on Auto-Tune 7’s new time manipulation features.” – antaresaudio
For more info: antarestech.com