9. Bill Gates
In a fourth season episode where Sheldon is experimenting with a virtual presence device, he spots Steve Wozniak at the Cheesecake Factory and proclaims him his "15th favorite technological visionary." While we'll never be able to see Steve Jobs, Sheldon's 21st favorite, appear, it begs the question of where Bill Gates would rank on the list. From what I've seen, the guys seen to prefer PCs to Macs as their home computers. However, my main reason for wanting Gates on the show calls back to an earlier episode where Raj and Howard recount to Raj's sister Prya how Gates once punched Sheldon in the face. Why? Sheldon said to him, "Maybe if you weren't so distracted by sick children in Africa, you could have put a little more thought into Windows Vista." It would be fun to see an episode where Gates comes to the university, prompting Sheldon to approach him and give another insensitive comment. The obvious result would be another punch to the face, but it would be so great to see Gates himself actually doing it.