ANH swordfight, which is technically the WORST swordfight in the movies.
I totally agree with that. I'm afraid I got a couple of facts wrong - my imagination obviously isn't as good as I thought it was. 
When I said the rocks falling on Yoda, although that is also terrible, I think I meant the weird thing that falls on Anakin and Obi Wan more, because the stuff coming off it looks terrrrrrribly fake.