I don't wanna trump Israeli equipment or soldiers just cause I'm Israeli, but the IDF has fought some fairly tough wars. 1973 was especially tough beacuse of the Intel breakdown.
As for an adaptive enemy, I think the Egyptians played that role fairly well up to a point in the Yom-Kippur War.
The War of Attrition was tasking and demanding as well, due to the fact that no official war was declared and the situation was mainly like it is today with the Intifada.
From 1982-2000 in the Peace of Galilee war Israel was forced to fight in both an urban and non-urban battlezone. One example of the IDF apating was using AAA units sch as the Machbet (An M61A1 Vulcan and a pod of Stinger missiles an on M-113 chassis) again's terrorists and against buildings.
I'm no expert on the subject and I'm eager to learn, so I await your comments, Ray, OOE, and everyone else