When it comes to the importance of victories, too much emphasis is placed upon weight class.
After defeating Matt Hughes, people acted as if Penn had just elevated himself to a new level.
Hughes was once a true pound-for-pound fighter, but last week he wasn't even a Top 10 welterweight.
More important than beating guys in multiple weight classes is being able to beat the very best in any one weight class, and at the present time, Matt Hughes isn't one of those guys. Georges St. Pierre and Frank Edgar are those guys.
That said, there are plenty of highly ranked fighters Penn could beat at welterweight, all the way up to heavyweight.
If he's motivated, Penn has a very good shot at beating Jon Fitch, the No. 2 welterweight in the world, and a P4P quality fighter. But victory against Fitch is far from certain.
Here are 10 fighters I'm far more convinced a motivated Penn would be likely to defeat...