I don't have any experience with anything except Autotune, which I found was fairly miserable in manual mode. Worked fine automatically, but the manual mode sucked.

Lately I've been using GVST's FREE "GSnap" plug-in. You can use MIDI to zero in on bum notes, or use it in automatic mode. I can't lie and say it's the 'highest quality available', because I honestly don't know. I'm using it because I have access to it, which is something I can't say for Melodyne or whatnot.

Greg

I have used auto tune with some ammount of success, the samples from the melodyne site do seem to rock Autotunes socks though. . .

Melodyne was supposedly used on eminem's vocals on quite a few occasions, so I believe that's as much of a quality as one might get - I'm using it a lot to fix bogus singers and its ability to snap to a scale is a godsend for those usual untrained pop/rock singers who don't (intend to) get out of scale or change key anyway. It also automatically detects vibrato and slides, so these don't get massacred by melodyne. It does, however, have quite a learning curve, at least it had for me.

I am going to get it for Xmas, I am quiet good at learning curves, I have extreme OCD so i will just use it solidly for a good week or so in 12 hour shifts. Thanks For you're help everyone. Merry Xmas Shopping everyone.

Get the demos, you can download them for free. Try before you buy. Also, check out waves tune. Its basically waves answer to melodyne. I've been playing with waves tune, and I think melodyne is still the winner in pitch correction.
Melodyne works best for me since I can work stand alone with melodyne, saving my cpu power. I then export the pitch corrected tracks back into pro tools, and no longer have to cry every time I need to "increase hardware buffer size".
If you have a full blown HD system with all the processing power at your disposal, I'm sure waves tune would rule in sound quality and ease of use.