Shoshannah,
I'll go so far as to agree with you on a construction such as "Where are you at?" which can be easily replaced with "Where are you?" Other than that, nothing else to say on the matter for right now. I'd like to hear what others have to say.

Dr. Bill,
I think it's: "A preposition at the end of a sentence is something up with which I shall not put."
And, another favorite, from the little kid gong to bed: "Dad, why did you bring that book I didn't want to be read to out of up for?"