Well, most professionals equate "autism" to Autistic Disorder, i.e., childhood autism, Kanner's syndrome, classic autism. Asperger's is an adequate term for someone who is autistic, but has a high verbal ability, plus different and more "normal" repetitive behaviours compared to Autistic Disorder.
Daniel is your friendly individual who often looks like a "ret*d"; I know that the people are looking at me when I sway, flap; walk with my head down and offset to the right, my left-hand curled up against my chest, and I apparently don't acknowledge their existence.
If anyone wants to call themselves "autistic" when they have Asperger's, that's cool, but don't call me "low-functioning", as I'm not.