If you are going to a World Top 5 - then it might be worth it to network with the people who are going to be hiring CEOs.Maybe not even then. I don't have the reference in front of me, but I seem to recall something about a study of the Fortune 500 CEOs, and there were as many from some state school (University of Wisconsin, maybe?) as there were from Harvard.
Edit: some links about this point.
http://content.spencerstuart.com/sswebsite/pdf/lib/2005_CEO_...
(Warning:PDF)
http://bernardmoon.blogspot.com/2009/05/go-wisconsin-most-fo...
http://www.usnews.com/education/best-colleges/articles/2011/...
Here's another fun observation from that 2005 study (said as a North Carolinian who resides in Chapel Hill):
Of the Fortune 100 CEOs, the top schools for their undergraduate degrees were:
Harvard, Stanford, Yale, U. of North Carolina - 3% each
Which one of these is not like the others? :-) (To be fair though, even though it's a state school, UNC is generally pretty highly regarded and their business school is usually pretty high in the national rankings.)