Bruce Almighty said:
Best is Freddie Mercury. Nobody is rock history combined amazing vocals with amazing showmanship. The only person that should be in the same discussion with Mercury is James Brown.
Favorite is probably Joe Strummer of The Clash.
Love Feddy, but Plant had the voice and showmanship. Plant really took what Jagger and Daltry did and perfected it.
I wouldn't argue with someone that has Freddy above Plant, but to say no one combined amazing vocals and showmanship just seems like Hyperbole and I think Freddie would pretty strongly disagree.
For me, Plant is the epitome of what the frontman is. He may have not been the best singer, but he was f'ing amazing and had that unique ability to appeal to guys and girls.
Jagger and Daltry are up there. I would prob put Freddy second.
And he's been mentioned here - Axl. Axl did things vocally that no one else could do. He was so unique and his energy was incredible. Go back and watch some youtube of them in the late 80's when they were really in their element. Axl was an incredible front man.
Vedder is great. Cornell was great.
One other point, I don't think of guys like Hetfield, G. Lee, Grohl, etc as front men because they are major instrumentalists. Maybe I'm being too rigid on my definition, but I don't consider those 'frontment'.