Gears of War VS. COD4 VS. Halo 3?

Gears of war was fun, loved the story line and game play. Online was more then I wanted. COD4, online is fun, but I found campaign super boring. Halo 3, majorly addicting, campaign never gave me a dull moment. Online is superb. Except for the occasional bullshit moments no complaints. Which do you guys like better? GoW, COD4 or Halo 3