The people who are voting zombies are probably plain liars.
I can guarantee with 100% confident that there will be not one person who will not go to multiplayer to play a single match. I bet the multiplayer will be awesome because thus far, I have enjoyed World at War and Black Ops the most (WaW more

). Also, I love CoD multiplayer. If they only had zombies, I would only buy it if they increased the number of players per map.
So, I am getting it for both simply because if I get bored of one, I can simply go to the other, and yes, zombies does get boring after you play one match up to Round 35, which takes probably 2 hours with 4 people, and then you just want to relax and play a nice game of TDM to end the CoD session.