Some of you seem incredulous that anybody would let this influence their purchasing decision. You have to keep in mind that most posters here are very price inelastic and would buy a Mac regardless (like smokers buy cigarettes, forgive the metaphor). There are a lot of people, like me, whose decisions are based off of making a Mac as affordable as possible. That means taking advantage of every possible offer. If you want to call me cheap, that's fine, but the new Dell XPS 15z at $999 with 6 GB RAM, i5 processor, 1 GB dedicated graphics, and oh yeah, free Xbox 360 is looking pretty good right now.
http://www.dell.com/us/p/xps-15z/pd.aspx
Not all students are wealthy enough to buy any electronics they desire. The old offer was a nice gesture that made an expensive computer realistic for students.
And to those saying "Apple is giving you $100, don't complain"--they're not "giving" me anything when I have to spend $1000+ to get it. They are not being benevolent for the sake of being benevolent.