ED2!! Too many great scenes to forget, although AOD does come close. I love it when the knight takes out his sword by kicking that guy away who's proffering it to him.
ED2 for sure.
I couldn't choose one so I took the easy way out and chose the "are you crazy, they're all amazing" option.
Also, if you can try to find Within the Woods, which was a prequel to ED. The quality isn't very great, but it's interesting to look at things before they got a slightly larger budget.