Your GPA does matter...until you get your first job or internship. From that point on, no matter how cliché it is, it truly will be about "who you know." A prospective employer wants to know two things: 1) "Will they do good work?" and 2) "Will they do it on time?"
Yes, good grades are one indicator of this, but an even better indicator is someone they know calling them and vouching for you. If you're going to go after the grades, do it for yourself, not for your future boss who dropped out of community college. All that your college grades will get you after the fact is a commiserating glance from the guy next to you at the bar who also graduated summa cum laude.
Exception to the rule: If you're applying to grad school, your undergrad GPA matters. After you graduate, the above once again applies.