I think that the scan-as-you-shop style systems are definitely the next realistic step for grocery stores. I really like using them, as they allow me to put stuff directly into my bags as I go.
I think a further improvement on a system like that would be to use the cheap RFID tech (UHF EPC) so that when you walk through the anti-theft barriers, the system knows exactly what you got, and then there's no need to scan anything.
I think a further improvement on a system like that would be to use the cheap RFID tech (UHF EPC) so that when you walk through the anti-theft barriers, the system knows exactly what you got, and then there's no need to scan anything.