FWIW, and I'm not in CS or IT, but I do work at a major university in the Cambridge, MA area in the Life Sciences and I can honestly say that nobody ever asked me (or anyone else I know) about GPA. When I've interviewed people looking for a position in our department, work experience, the ability to understand what I'm talking about, and being mentally agile have mattered way more than anything else. Then again, we're not in the habit of hiring people for their first job out of school.
First jobs suck. I'm not talking about working retail in high school or something like that, I'm talking about your first job after some kind of real training. It goes with the territory. You get that first job, you get shit pay for a couple of years, you find a new job and things get better.
This is, of course, assuming you absorb the important things about what you're there for. If you show up to work and you lack the basic knowledge about how to do your job, then you wasted your time at school. It's possible, like you pointed out, to get good grades in your primary field of study and get mediocre to lousy grades in other things and still turn out okay.
If you take some other job unrelated to your major just to pay the bills, though, don't ever stop looking for something more related to what you want to do. Once you lose the job search momentum, it's hard to get it back. Don't get comfortable in a crap job, basically.
