Monte Cassino in WW2 might be another good example of taking a hill (or not taking a hill), although a lot of the fighting was in the town at the base of the hill.

The Allies lost a lot of men trying to take the town and hill. But I remember reading the comment of the German paratroop commander defending it. He said the Allies had just not committed enough men in one assault. This was surprising as the concentration of force in a very small area was already impressive.

I think in the end Monte Cassino fell in something of an anti-climax, when flanking moves had meant it was no longer so vital for the Germans to defend and could be attacked from the rear.

Talking of hills, I was surprised to read in the context of Vietnam that the US army learnt to prize maneouvring through valleys rather than trying to secure the high ground. IIRC, the thinking was that people out on hills made better targets whereas valleys offered more concealment. But maybe that just goes back to the "blow up the hill" point. I suspect the modern US army would just love it if their opponents were foolish enough to set up on a hill to oppose them. (Gets me thinking of the "We were soldiers..." film I saw the other day.)