The first of these, what I term "disease models", view autism as something that someone gets. An example of this would be Generation Rescue's "mercury poisoning" theory. The GFCF diet, chelation, and a number of other "biomedical interventions" are based on this sort of view of autism.
While there are a number of issues with chosing a representative slogan and/or quote that summarizes these models, "love the child, hate the autism" (for a slogan) is pretty good. Another good quote, taken from the introduction to Jenny McCarthy's new book, is the following: "Autism, as I see it, steals the soul from a child; then, if allowed, relentlessly sucks life’s marrow out of the family members, one by one.."
I do not think that I have to explain exactly how offensive this sort of thing is. Of course, I could be wrong... but determining that is part of what the comments are for.
The second category, what I call "disorder models", view autistic people as inherently broken. A number of these can be found in the academic literature... but the DSM is a prime example.
While most modern theories fit in this category, Autism Speaks's puzzle piece symbology is usually considered representative of this -- "Together, we'll find the missing pieces"... as if autistic people are defined by missing something (and, usually, this means "something that makes us human", implying rather strongly that autistics are therefore less than human).
The usual response to this is something to the effect of, "I am not a puzzle. I am a person."
The third category, what I term "strict-disability models", hold that autism is, at its core, an inability to do something (or some set of things). There is considerable evidence directly contradicting this, but people continue to endorse this sort of view... usually by confusing autism's DSM-IV diagnostic criteria (i.e. the "triad of impairments") with its definition (i.e. the underlying neurological and psychological differences that set autistic individuals apart from neurotypicals). Well, that or they go through some of the same intellectual contortions commonly used by supporters of disorder models.
The fourth category consists of what I call "difference models". These hold that autism is a set of neurological and/or psychological differences. Note that I do not say disfunction or disorder -- what distinguishes these is that they don't consider autistic brains (or minds) broken.
Finally, there are the social disability models. These define autism as a developmental disability based on the social model of disability.
Personally, I prefer the last two... and they're what the available scientific evidence supports. See pretty much any of Michelle Dawson's articles for review.