Current procedure in my Airline (an Australian major) is for COM1 to be used for all ATC transmissions, and COM2 to be used for Weather & company, and "parked" on 121.5Mhz at other times. Exceptions are for OCTA work (COM1 on MBZ "Aerodrome traffic" freq. and COM2 on Area) and PRM monitored approaches at Sydney, as mentioned previously.
However, when I joined six years ago, they did indeed have both COMs set to the same frequency, and the pilots crosschecking that each could recieve ATC on each COM at each frequency change. Strange but true.