3. Eddie Izzard
Sylvester McCoy and Tom Baker have both hinted in the past that they think comedian Eddie Izzard would make a great Doctor. So much so that there has even been confusion about whether or not he'd nabbed the role. Both former Doctor's cited his quirkiness, comedy and intelligence as reasons he'd be a good fit. Apparently Izzard's even had his eye on the role since the shows revamp in 2005. I believe Eddie Izzard could bring some intellectual and comedic genius to the role, but his Doctor would also be eccentric to the point of being unrelatable. Izzard's Doctor would be scheming and maniacal and hard for his companions to trust. His cross-dressing might appease some fans looking for a female Doctor, but in a very unsettling way. He'd be a Doctor who enjoys setting things in motion and watching them unfurl. In fact, I think Izzard would make a better Master than Doctor.