I will say the David Tyree catch was the best catch and the greatest play I ever seen
There are many I'm a fan of Sehorn's Int and Bavaro's catch and Shockey trucking Gibson and so many of LT's and so on. But undoubtedly due to the game, the time of the game, the stakes and the opponent it happened against and the significance of what it did for Eli the helmet catch is the greatest play in NY Giants history and its not even close.
One of mine was Giants v Vikings, 1986 Phil Simms 20 yard pass to Bobby Johnson on 4th and 17 with 1:12 left on the clock. Kept us alive for the game winning field goal.