I like WWII
The first thing that happened when news broke that Treyarch was making the next Call of Duty game and it was going to be set during WWII, was people lost it. "HOW DARE THEY GO BACK TO WORLD WAR TWO!"
I loved Call of Duty 2 and 3 and of course got way into Call of Duty 4. And Now being a part of the Call of Duty World at War beta, I realize I really like WWII as a setting way more than a present day battlefield.
The sights and sounds are just way more atmospheric than a modern day battle. It really takes you back to another time when wars were not fought from hundreds and hundreds of miles away with missiles, they were fought up close and personal.
Modern day may have impressive technical weaponry, but it does not have the unique architecture, vehicles, and all around vintage feel. The sounds of an Artillery strike laying waste to the other side of the map is truly something unmatched by a current day air strike.
I also want to talk about some of the Gameplay. In Modern Combat you have Air Strikes and Helicopters as rewards for kill streaks. In World War 2 there were no Helicopters to be found on the battlefield. Instead you have DOGs, this may not sound very menacing but OMG, you don't realize how fearsome rabid attack dogs truly are until you are being killed over and over again by a bite to the neck. Easily you can take one or two down, but can you take down 3 without them ganging up on you and deal with the enemy team firing at you? Its a fantastic change of pace for the multiplayer component and it works extremely well. Whoever at Treyarch Said "I Know, lets do Dogs!" should get a raise.
Maybe I just have not become over saturated with the setting yet due to having Call of Duty being the only real WWII Series I have played but tonight I learned that I like WWII better than Modern Combat.