Considering Machida's biggest win is over Sokoudjou fighting Liddell could bring him the kind of exposure he'd need to be a legit title contender in the minds of the casual fans. Even losing a competitive match to Chuck would probably give Machida's image a boost.
Honestly were the fight made tomorrow I'd probably pick Machida. I think his striking style is kind of the perfect foil for Chuck. He gets in and out with his strikes quickly enough that Chuck's counterpunching would lose it's effectiveness. The Jardine fight still provides a good blueprint for how someone like Machida could take Chuck out.