Hewlett-Packard: I'd give that one to Stanford way more than MIT. From Wikipedia:

"Bill Hewlett and Dave Packard graduated in electrical engineering from Stanford University in 1935. The company originated in a garage in nearby Palo Alto during a fellowship they had with a past professor, Frederick Terman at Stanford during the Great Depression. Terman was considered a mentor to them in forming Hewlett-Packard."

If anyone's interested, here's a fuller list of SV companies founded by Stanford-affiliated people: http://www.stanford.edu/group/wellspring/economic.html