I think much of it comes down to what you're shooting. Being able to get wider angle shots that have a small depth of field is really awesome to me. I'll agree with you that for many situations, smaller depth of field isn't necessary.
From what i've seen the 5d performs considerably better in low light for photo. I know this isn't a scientific comparison, but just by looking at star time lapses, the 5d produces a noticeably cleaner image than crop sensor cameras.
Having said this, I still can't justify spending over double the price of a 60d to get full frame.