The film is The Whole Wide World and, though I've only seen a bit of it, I have some strong quibbles with the presentation of Howard... that is, the way D'Onofrio portrayed him in the bit I saw (the rest of the film may have been very good... eventually I'd like to see it all and make up my mind from that).
As for Arnie... well, I encountered Conan many years before the film was made, so that wasn't a problem for me. Besides, with that description of the Cimmerian standing over his former mistress' paramour (after he'd gutted him) "ghoul-like, his eyes burning in the gloom" in "Rogues in the House"... I rather think I'd not have been seeing Arnie at that point, regardless.....
Basically, that was what I liked about the way Howard presented the character. He had (despite his supernatural adventures) a feeling of depth and reality to him; he could be brutal, cruel, and sinister (as above), at the same time, he could even react to an alien creature (once over his initial shock) with compassion and empathy:
Tears rolled from the sightless eyes, and Conan's gaze strayed to the limbs stretched on the marble couch. And he knew the monster would not rise to attack him. He knew the marks of the rack, and the searing brand of the flame, and tough-souled as he was, he stood aghast at the ruined deformities which his reason told him had once been limbs as comely as his own. And suddenly all fear and repulsion went from him, to be replaced by a great pity. What this monster was, Conan could not know, but the evidences of its sufferings were so terrible and pathetic that a strange aching sadness came over the Cimmerian, he knew not why. He only felt that he was looking upon a cosmic tragedy, and he shrank with shame, as if the guilt of a whole race were laid upon him.
Incidentally, as of August, there's a new book that might be of interest for those wanting to try different aspects of Howard's work; especially those coming to him for the first time:
Del Rey Online | The Best of Robert E. Howard Volume 1 by Robert E. Howard
There's to a follow-up volume this month (or perhaps next, with scheduling being off with so many publishers lately):
Del Rey Online | The Best of Robert E. Howard Volume 2 by Robert E. Howard
There's a lot more to Howard than Conan, certainly... even though I do have a great deal of fondness for the character the young Robert Bloch once called "the Cimmerian chipmunk"....