My choice would be the final 1979 against Arsenal. Liam Brady was having one of his days and they tore us apart in the first half and at half time we were already 2-0 down. 2nd half Gordon McQueen pulls one back in the 86th minute. Then in the 88th minute McIlroy gets on the end of a pass from Coppell, goes past 2 defenders and scrambles the ball into the net. Then before the celebrations died down and everyone getting ready for extra time, Brady still causing a threat, picks the ball up in midfield, goes past 2 of our men, slots a pass to their winger, the cross comes in and Alan Sunderland scores in the 89th minute. This one because of the disappointment!