The 'Adam' clips I saw on the chat shows weren't very impressive - it certainly didn't make me want to go see it, but as long as it doesn't portray Autistics as serial killers or ret*ds, any portrayal in the media is helpful in making audiences accept us as people. I just wish the writers at BBT would out Sheldon once and for all. Even when he's annoying he's funny and he'd make a great poster-boy for AS. Ba-Zinga!
My only issue with Rainman is that in the film, Raymond is referred to as 'High Functioning' when he clearly is not. His basic behaviors and reactions to stimuli I think are very authentic. I identified with them very strongly the first time I saw the film and that was nearly twenty years before I'd heard of AS, much less been diagnosed. The stimming, the "I don't know" answer to nearly every question he was asked, his panicky aversion to deviating from his routines, the insistence that his underwear come from not just KMart, but one specific KMart - all exaggerated for Hollywood dramatic effect, but all made perfect sense to me. I am that guy, I just hide my differences better than he does (though I realize now, not as well as I once thought).
Of course giving the public the impression that everyone with autism has some amazing savant ability is not helpful, but the movie never says Babbit's savant talent is connected with his autism. People just connect dots that aren't really there - 'His autism makes him different in some ways, therefore every difference he has must be due to the autism'. Not at all logical, but a common assumption.