I also prefer main packaging for the cover, but being as I don't have a scanner right now that's worth a crap I have to make do with what I can find on the net at the time - if someone else can replace it with a better/more appropriate image, great.
That said, some CE's are HUGE and you can't exactly scan the box. And I *hate* weird angled non-professional photos. I can't tell you how much this image bothers me:
http://vgcollect.com/item/63677
The perspective could be easily changed with photoshop or gimp, given that someone has the full res image... Other than that, the only option I see for big boxes is to have a professional quality photography set and take a picture from a perfect angle at the front, which requires lots of material to do