That August 2011 8" of rain at JFK is very memorable- and it came a month after we hit 104 degrees and 108 degrees at Newark! In August 2011 we also had to deal with the rains of Irene and a 5.8 earthquake!
Chris, a storm that just missed this list though it comes close is the January 2016 Blizzard which was a 3" liquid equivalent (31" of snow) at JFK!
That May 1, 2014 event is also memorable for all the flooding we had with widespread 5" rainfall totals (mostly at night)!
Interesting I had forgotten that in March 2010 we actually had two big rainfall events, like we did in August 2011.