The 1m mark tends to be the benchmark for 'outstanding' sales these days on any platform. The 300,000 mark is generally the break-even benchmark for Wii titles as House of The Dead Overkill has shown (although that does depend on the budget used for the title obviously). I'll be very interested to see how much it manages to sell after a month in each territory, I'll guarantee you that it'll be generating profits for Sega by that time.
I can see publishers fighting tooth and nail to get hold of The Grinder, although I suspect that Sega already have a deal in place dependant on sales of The Conduit.