I don't agree with denoting it as "reverse discrimination". Discrimination is discrimination no matter what, regardless of who is the discriminator/who is being discriminated against.
That being said, affirmative action does have its merits, although I do think that socioeconomic status should have higher priority than race in things like college admissions, although in many cases SES and race are closely linked together. It all comes down to how many opportunities a person is given. Diversity is a major issue, though, and I feel that without programs like affirmative action college campuses (particularly older universities with small admissions rates, such as my own) would be dominated by white upper-class individuals whose families have those connections and resources to support their children by helping them procure internships, volunteer abroad, get expensive private SAT tutoring, etc. Racism and discrimination are both also still very much alive in this country.
Edit: While I'm at it, here's just an interesting Tumblr blog created by Harvard students which illustrates just how rampant racism still is in society and how minority populations are often marginalized in many universities.
http://itooamharvard.tumblr.com
These misconceptions are precisely why diversity is so important.