I just watched a cool video from Graham over at The Recording Revolution, showing how he turned one of his songs from one that was a bit boring (his word:)), to one that really popped. He did this using just one plugin - a vocal pitch effect similar to Antares Auto-Tune and Harmony Engine EVO. It was called Neptune Pitch Adjuster & Voice Synth, which is part of a recording software program called "Record," by Propellerhead. Of course, you can do the same thing with other DAWs and vocal pitch and harmony plugins. I use Reaper as my main DAW, and you can use any VST plugin with Reaper.
Anyway, the key here was that Graham used this effect to create contrast in his mix, making it more interesting and complex. He used a combination of extreme vocal pitch tuning - think T-Pain or that one song by Cher in the 90s - along with a sort of robotic sounding harmony generator creating some nice vocal harmonies on the verses. Then he left the vocal on the chorus untouched by those effects such that the natural sound of his voice there is very different from what it is on the verses. The overall effect is a mix that now pops more.
Watch the video - and more importantly - listen to the before-and-after audio here: