Been running for about a week with System Activity and Attacks checked.  Getting a lot less information, but I'm still not seeing any blocked ping requests.  Just tried pinging my machine from the office and it doesn't show up in the log.
As I mentioned earlier, my older DIR-655 (A4/1.37NA) showed all the blocked ping requests.  I'm convinced this is a bug in the latest firmware.  How would I go about reporting this to D-Link?