I use vocal processing. The TC Helicon in the Korg automatically will set e.q., compression, de-essing, etc., or you can do it manually. It instantly sample the singer's voice and optimizes all the processing. Works great for me!
Also, reverb and/or delay is part of processing, all totally editable.
I do also use vocal harmonizer, but try to use it tastefully. I generally use one harmony voice, a third above my voice. There are some songs when using it on a line or two, or on the chorus helps a lot.
Sometimes if I have a guest vocalist, or on the rare occasion when I work with someone else, I can use it do to group background oohs and ahhs, or whatever.
It's another tool in the arsenal, but a great one.