At the risk of being flamed:
I thought I'd share my thoughts on the use of Melodyne and similar technology. I fully admit that I use the plugin on many of my vocal tracks (I'll go one step farther and admit I have no vocal talent what so ever).
I feel that Melodyne can be used as a creative tool, and that is the way I tend to use it most. Being in a one man band situation, I'll typically record a scratch vocal close to what I am hearing in my head. It a rare occasion that I actually get it right on the scratch vocal take I try to double it and move on. When I don't nail it is where I use Melodyne as a composition tool. It allows me to try different melodies and rhythms to tweak the lines to my liking. I usually then sing along to the altered scratch track for several takes and comp the best bits together. And yes, i may use it to fix intonation issues on the final takes if there is a need.
My point is that Melodyne can be a creative tool for composition that allows experimentation that would otherwise be difficult for many to achieve. I'm not using it to try to fool anyone, I am simply attempting to compose a song thats conveying the mood, feeling and ideas that originally inspired the song. I am in awe of, and take my hat off to those real singing talents that can nail the perfect emotional, moving vocal on the first take. Unfortunately I don't have one of those at my disposal.
Fireproof underwear now on, flame away!