With the release today of Call of Duty: Black Ops we already know that developer Treyarch and Activision have another hit on their hands. The big question is how many copies it will sell, and according to a number of retail sources, it is now expected that Black Ops will top Call of Duty: Modern Warfare 2 in sales.

Retailer GameStop had most of its stores in North America open at midnight for the launch of Black Ops, and fans were lining up at retailers as early as noon yesterday eagerly awaiting their chance to get their hands of the title. GameStop isn’t the only retailer that received higher than expected pre-orders for the game. Sources confirm that they have more pre-order copies of this title than they did for Modern Warfare 2, which, of course, is a good sign.

While Activision isn’t talking numbers yet, it is a given that they are expecting the game to became the best selling game ever, or close to it when Tuesday ends. Activision has placed a much larger promotional push behind Black Ops and it is expected that the title will deliver. The midnight launches have gone well and now it is more of a question of how quickly the remaining copies that retailers have will sell.

Retail contacts we spoke with claim to have ample stock of Black Ops, so we will have to see if this is still the case when Tuesday ends.