I have to admit that, if all things were equal, I would probably look upon the graduates of Yale and NYU more favorably and possibly also those from Smith and MH. The tricky part about the admissions process, though, is that things aren't going to be equal enough to make that sort of direct comparison very often. Also, as soon as you get to the interview stage, all bets are off. If you don't come across as personable and capable, it's not going to matter where you graduated from.
It's not really fair that people judge others based on their undergraduate institution, especially when so many students make their desicions for financial reasons. People make snap judgements based on all kinds of criteria, and those judgements are also often unfair. It's simply the way people are and it seems unlikely that those particular prejudices associated with prestige are going to change any time soon in the modern, merit-based world.
The way I see, it, in most cases, if a person graduated from a reputable undergraduate school, it indicates a certain level of achievement and ambition in their younger years. If a person graduated from a school with less of a name, it doesn't mean that those qualities were missing, it only means that one may have to look for other, perhaps less obvious, indications of those traits.