Jack Johnson if you can find footage of him. The uppercut was his best punch. http://www.amazon.com/Joe-Gans-Biography-American-Champion/dp/0786439947/ref=pd_bxgy_b_img_b
you shouldn't try to copy another guys uppercut. you should just keep working it during sparring and eventually it will happen. for things like that you need to find out what works for you or find good pro fighters with builds/styles similar to yours and watch theirs.
I always loved how RJJ through an uppercut after a lead leaping left hook. Tried it once though in a big fight and it didn't turn out as well as I saw it on HBO :hat
I'd go along with Zab Judah - best uppercut that I have seen for a long time. Accuracy, timing, speed, power etc, he throws it damn near perfectly.
I think it depends on your style. If you fight like Tyson there's not much use in mimicking Floyd when setting up an uppercut.
Ricardo Lopez Highlight: http://www.youtube.com/watch?v=fQfc58XeQXQ Zab Judah Highlight: http://www.youtube.com/watch?v=TtS-jCIT1Ac James Tony Highlight: http://www.youtube.com/watch?v=Zo6f6C9ztPM Just for fun: http://www.youtube.com/watch?v=_0cCHWnWRe0 http://www.youtube.com/watch?v=CojLCBasvNU
Yeah it does depend on your style mate, personally i get in close and do uppercuts and body shots so the best fighter for me to watch is ricky hatton. but if your less aggressive id say kessler has a pretty mean uppercut. watch the Haussler-Kessler fight and he knocks him out with a wicked uppercut