If Shakespeare hasn't already convinced you that Richard is bad, bad, bad, perhaps the great actor John Barrymore can. This speech, filmed in 1929, is technically from Henry VI, part 3, but parts of it are sometimes included in Richard III performances (notably Laurence Olivier's). Check this out...
Ooooooh, scary! I'm glad I'm not related to *him*!
To appreciate how amazing-kamazing Barrymore was, compare the video above (of him being Richard) with the video below (of him being John Barrymore, on a well-behaved day). This is his introduction to the Richard soliloquy. Does he even seem like the same person?
There are a lot of Richard videos out there. But Barrymore sets the curve.