1) John Steinberg, Nobel prize winner in literature. He attended Stanford as an undergraduate twice, but dropped out without a degree.
2) Steven Balmer, CEO of microsoft. He attended Stanford bussiness school without finishing his MBA. Bill Gates lured him away.
3) Andy Bechtosheim, employee #1 in SUN. He attended Stanford as a ph.d student in computer science. He stayed at Stanford for 5 years, and invented the networked SUN work station on its campus, but dropped out without a ph.d degree.
4) Whitfield Diffie, one of the founding fathers of public key cryptography, noted for Diffie-Hellman-Merkle public key exchange. He was a ph.d student under John McCarthy (father of artificial intelligience) and later under Martin Hellman. But he left Stanford without a ph.d. degree.
5) David Filo, co-founder of Yahoo, dropped out from Stanford EE Ph.d. program
6) Jerry Young, co-founder of Yahoo, dropped out from Stanford EE Ph.d. program
7) Larry Page, co-founder of Google, co-inventor of GOOGLE search engine, dropped out from Stanford Computer science Ph.d. program
8) Segey Brin, co-founder of Google, co-inventor of GOOGLE search engine, dropped out from Stanford Computer science Ph.d. program