If a child has a learning disability they need the label in order to get the help they need to succeed. Also, a students special education records are confidential (I believe they're covered under HIPPA? as well as the IDEA). So many children receive pull-out help of some sort, that if you don't let other people know yourself, they should never find out. I, on the other hand, share what my son's disability is with many of the parents I know. I feel that when my son is behaving a little "off" it's easier for the other children to accept him if they know that his brain just worls a little differently.
When it comes to college, you do not have to disclose a learning disability unless you are requesting accomodations, and due the privacy laws they cannot find out. The only situation where an organization can find out about a students special education records without your permission is the military/government. Even then, there is only one label that will definitely hurt your child's chances in the military..Emotionally Disturbed. If your child has a disability that may fall under this category, it might be beneficial to them if you push to have them categorized under Other Health Impaired. Of course, if your child has a true emotional disability and the only way to get help was to accept the E.D. label, I would take it.