The problem with asking questions like this is that there's not really a 'right' answer, so the main thing is to get the candidate start talking. I would ask them to describe an architecture that they've implemented that they are proud of. And then follow up with things like, 'what about it are you most proud of?'. And you can then ask them what mistakes they've made in the past, that sort of thing.
I feel more comfortable about that because you getting a feel for the person, and not their ability to answer a canned question.
