OK, lets not flame pleiades too much for adding his opinion.
Yes if you lose power and cannot communicate you are correct in saying that you should continue as per your flight plan since through busy airspace etc it is the only way for ATC to know what you are doing.
However you are neglecting the golden rule of aviate,navigate,communicate. Note: navigate comes second.
In my A/C a total electical failure (requiring the failure of 5 seperate generators -well 2 from each engine and and the APU) is very unlikely. But we don't deal with purely 'very unlikely' so we have to plan for it and the battery power following this will last for 40 mins if you shed all uneccesary loads (according to the book anyway I would be planning to land sooner than that!). After that you would have (as has been mentioned) no AI - or other quite important systems! Admittedly you would still have one radio, but in the spirit of pleiades post lets assume you have an unconnected comms failure...
In the spirit of aviating first I wouldn't contnue for the remaining hour of the flight hoping that continental Europe will suddenly become VMC despite what the forecast said!