No, it's hardly sarcasm.
Students don't need additional motivations for wasting time in college. A free XBox is the equivalent of saying "don't study, play Halo instead!"
Yeah, because students never play video games without the encouragement off the manufacturers.
Out of the two, if I was a student, I'd go for the cheaper PC and get a free XBox. I imagine many will follow suit. Although, I also imagine a Mac is also still tempting to students. This however, is a good deal from Microsoft. If only non-students got the deal.