Is your alma mater an omnipresent tag to your identity (and résumé) or is it just four years of your life?
I'd put it somewhere in between. I'm just leaving the college process and what I'm finding is that in everyday situations it doesn't matter where you went to college. However, the part that they don't tell you much about heading in is that where you go affects what doors are open to you. Certain companies (in engineering at least) are much more keen to hiring from certain colleges, and that can affect a persons ability to get into an entire industry or geographic location of the company. It's an omnipresent tag if you keep finding yourself in situations where the person holding the keys either went to your college or holds it in high esteem.