I was going for Tony Montana
Completely unscrupulous and probably malevolent with it.
( Lord Gnome, Sat 23 May 2009, 19:44, archived)

Anton from 'No Country for Old Men'
www.imdb.com/character/ch0027247/
(rigby happened on (and with added toothache), Sat 23 May 2009, 19:50, archived)

Or Idi Amin
From Last King of Scotland.

Or Adolf Hitler from Triumph des Willens.

It's a fairly open question.

[Edit] I am a mong- I even said "fictional" in the question.
( Lord Gnome, Sat 23 May 2009, 19:55, archived)