If you are talking about the LFE crossover, you want it at 120hz. The crossover for your other speakers should be set for the speakers capabilities.
I cross all my Klipsch at 80hz, and run the fronts as "Small" and the center as "Small". LFE xover of 120hz.
One thing about the crossover settings for the mains, center, etc... Once Audyssey is complete and saved, you can raise a crossover setting, but lowering it could cause issues. For example, Audyssey sets my fronts as large and full, and my center as small and 40hz. I change the fronts to small and 80hz, and the center to 80hz. If it had set my center at 100hz, per audyssey rules IIRC, I should not adjust down to 80hz.
65" VT50 / BDT460
X4000 / Outlaw Model 7125
Klipsch RF82 II and RC62 II / Hsu VTF-15H (2)
Directv HR44-200 / HR24-500