I think after Castillo Floyd stopped challenging himself. I think up till that point he was willing to fight anyone, anytime, to prove he was the best, to prove he could beat them. After that, I think he probably started looking at things a little different, maybe looking at easier paths and then only the big money fights.
Recently, the mosley fight was a very good win, and that was a bit of a challenge and he deserves credit for it, but still under the circumstances it sort of felt like he had to take the fight rather than he wanted the fight. Nonetheless a great win for him. But really since Castillo, not too many big challenges - Gatti, Baldimor, Judah, Oscar, Hatton...Solid wins, but missing the tough opponents the Cotto's, Margarito's, Clottey's, etc. and there always was an excuse not to fight someone not enough money, they lost X amount of times, etc etc etc.