The answer to the above question is yes and no. While the main campaign in Call of Duty: World at War is fun and gripping, and it helps that the game avoids D-Day and Normandy, instead focusing on fighting the Imperial Army in the Pacific and taking back Stalingrad as the Red Army.
Still, it's not enough of to change to convince one that this isn't just another World War II game. It's a fantastic World War II game, and that definitely counts for something, but it's familiar enough that some people might be turned off.
However, a great plus is being able to play through the campaign with up to three other players. Cooperative gaming is becoming more and more popular and for good reason; it's a hell of a lot of fun.
Treyarch's bonus zombie mode, as small as it is, is definitely worth mentioning here. When you beat the main campaign, you unlock a special mode that puts you (and up to three friends) in a bunker being overrun with zombies. Your job is to fight them off while earning better weapons, as well as repairing breaches in the bunker. There's no ending; you just survive as long as you can. It's amazing fun and with the WWII weaponry and the traditional slow-moving undead, it provides a different experience than the recent hit Left 4 Dead.