Well Chris would clearly win. He's more experienced, stronger, quicker and a better shot. Plus I don't believe that Leon is the only man or thing that Wesker is afraid of. Nope that spot goes to the hero of the story: Chris Redfield.
Also nice pic, only problem I see is with his left shoulder. Not trying to mess with, just trying to help a bit.
Haven't played RE5 yet (just RE4), but from what I've seen I'd think a gun fight could go either way. If it was close combat though I'd say Leon would win due to his awesome knife and martial arts skills while Chris mostly just tries to tackle or punch.