Hillary Rodham Clinton
The obvious answer is Tea Leoni.
I think John Kerry has had one of the most difficult jobs considering he's had to circumvent a recalcitrant and fearful administration to be effective. The Syria hearings were a good example of that. Overall I think he's probably been the most effective Secretary of State, and one of the most challenged, that we've had in a long while. I think Condoleezza Rice wasn't as effective nor was she as necessary given the strength of support she had from the administration and how her efforts were often secondary to ongoing policy from the administration. Similarly I think Clinton was competent but I don't think she was that severely challenged nor was she as aggressive as Kerry in pursuing policy aims.
Where is the 'None of the above' option?
'What kind of sick and twisted toy factory is this?'
'We are all the sum of our tears. Too little and the ground is not fertile, and nothing can grow there. Too much, the best of us is washed away.'
"Better to be dead and cool, than alive and uncool."
"I am not among those who fear the people. They and not the rich, are our dependence for continued freedom." -- Thomas Jefferson, 1816 "[F]acts are before ideas." -- Mikhail Bakunin, 1882
Albright wasn't in the 21st century unless you're trying to count the last 21 days of the second Clinton term. If I'm not mistaken, technically, the 21st century didn't begin until January 1, 2001.
As for the others, anyone who is/was Secretary of State under Obama is at a handicap since they would be reporting to Valerie Jarrett and Jarrett couldn't find her ass if you placed her hands behind her back, palms down.
As for the two Bush Secretaries of State, both served at a time when your country was primarily leading a world war and their time was spent traveling to secure coalition agreement. Seeing the troubles both Obama Secretaries have had in gaining any kind of cooperation on foreign policy issues, the two Bush Secretaries should get points for their success.
All that said, not a one of them is in the class of some of the very fine Secretaries of State to serve your country - my favourite being Kissinger.
A Canadian conservative is one who believes in limited government and that the government should stay out of our wallets and out of our bedrooms.