User blog comment:J1coupe/Ratchet and Clank vs. Jak and Daxter. Epic Rap Battles of Video Games Season 6./@comment-5872292-20141023094648

Here's one I hope is totally original and was never thought of or used: Chris Stone from Freedom Fighters vs Robert Jacobs from Homefront.

Both are main characters from third-person and first-person shooter games respectively in which you play as a rebel who tries to free 'Murica from a bunch of Commie Red invaders.