Also, what a lot of people overlook is that the whole point of the cloying sentimentality and artifice at the end of the film, is that it mirrors the sentimentality and artifice of David's creation at the beginning of the film. A very Kubrick touch, rather than the Speilberg schmaltz that many atttribute to this plot device. It looks like a happy ending, but beneath that there is tragedy in David's eventual destination in his journey to be human.
If I could have changed anything about the film, I would have made the "big city" scenes a lot sleazier (to hell with the rating!), and the "junk yard" scenes less redneck, and more cold and clinical - as if the idea of blowing robots up for entertainment was an entirely normal family activity.