Understanding that much of this depends on personal preference, I'd appreciate reading what others thnk and, perhaps more importantly, why. Not sure which exactly is important so I've include quite a bit of info below.
Receiver: HK 7200 - capable of setting crossovers for each speaker (20HZ-20KHZ)
Subwoofer: (JBL PB12) Low pass frequency: continuously variable 50HZ-150HZ High pass frequency: 150HZ when using speaker level outputs Frequency response: 25HZ low pass crossover setting
Front/Surrounds: (JBL S36II) Frequency response: 60HZ-20KHZ Crossover frequency: 650HZ, 3000HZ
Center: (JBL S-Center) Frequency response: 75HZ-20KHZ Crossover frequency: 800HZ, 3200HZ
I currently have the crossovers set at 80HZ for all of the speakers.
Crossover: Kegger suggests a good value (which is also the THX value for crossovers). I would have suggsted setting your crossover to 60Hz to test, but since your front speakers seem bass shy (don't go below 60Hz), I would leave it set at 80Hz. You may want to try 100Hz to see if that improves your bass response.