As pointless as this debate is, I couldn't resist jumping into the discussion. First, I generally agree with the above poster. The caliber of students entering the "ivies" (and I use "ivies" here to denote any highly competitive, research-intensive national university) is on a whole more academically talented and accomplished than that of an average state school. To deny this is a little stubborn and close-minded I think. To the poster who commented that a random sampling of a class revealed that he/she and 74 other classmates turned down "at least one ivy" to attend a state school, I would guess then that you attend one of the very good above-average state schools, i.e. UMich, UVA, UCLA, Berkeley, UNC, etc. I would say on the whole, these comments don't really apply to students at those schools, as they attract a strong caliber of students and provide a rigorous education.
The Valedictorians and Salutatorians at my HS who had captained state championship teams, composed 4-string quartet pieces, and performed nuclear engineering research went to Princeton, Stanford and Harvard. These are the types of students those schools attract, so imagine the academic competition that results from grouping all these students used to being high achievers into a single class. I would argue that the resulting academic work is of a high grade, but also that what is needed to distinguish oneself, getting an A for example, is more stringent. Therefore an A at Yale should mean more than an A at random State U. Think big fish in little pond moving to an ocean, where the big fish needs to excel even more in some way to survive.
All this is definitely not to say high-achieving, brilliant students can't be found at any State U. I would just posit the idea that at the "ivies" they're more common, which increases the overall quality of the work performed by the students and the difficulty in attaining distinguishing marks. I think people become defensive on here, because no one wants to be told, even in only an insinuating manner that their school is not as good as some other school or that their hard-earned GPA at another school would be worth less.