II is Bobby Fischer.
The odd one out
XI is Winston Churchill.
IX is Jamie Foxx playing Ray Charles. This must be the odd one out, since all
the other pictures are of the actual persons.

Churchill is correct, but it is the "real" Ray Charles on the picture. Good try, but keep looking...

Is III Kate Jackson?
Yes, this was probably the toughest! Only I, VI and XIII remain.

I'm guessing that all but one of them plays chess. I don't know this for sure, but I'm guessing it because:
1. This is a chess site :-)
2. I know I have heard of many of them playing chess (Fischer, Ray Charles, Will Smith, Sting, Keanu...)

I is Theodore Roosevelt
Oh and XIII is Nikola Tesla
Is VI Alan Dershowitz?
Roosevelt is correct, but VI and XIII are incorrect.

I'm guessing that all but one of them plays chess. I don't know this for sure, but I'm guessing it because:
1. This is a chess site :-)
2. I know I have heard of many of them playing chess (Fischer, Ray Charles, Will Smith, Sting, Keanu...)
Excellent, Loomis. All but one played chess. Can you guess which one didn't?
Who are the famous people pictured below? All except one have something in common. What is it, and who is the odd one out?
[Update]
All have been identified (Zankfrappa did most of the work - congrats)
The one thing in common for all except one is the ability to play chess (congratulations Loomis)
The odd one out was correctly identified by mprhchess, and it is Bing Crosby.