Although I wouldn't put Halo 3 at the top of my shooter list for Xbox 360.

1. Gears of War

2. Halo 3

3. Call of Duty 4

Anyways, on majornelson.com, Halo 3 is back on top of the Most Played Xbox LIVE Game list. Giving CoD4 a good shove. People say " Oh no, it's a fluke because of Cold Storage!" I honestly don't think it's a fluke, I know a lot of people who are getting really tired of Call of Duty 4, me included. However, while other people went to Halo 3, me and my mates went back to the legend that is Gears of War! I've seriously forgotten how much I loved this game, and I'm just having so much fun playing it again. Gears of War 2 will come out and will stomp on Halo 3. i personally think Call of Duty 4 will be undone by it's own game. Call of Duty: World at war will split the CoD Fanboys. Some will stay loyal to Infinity Ward and play Modern Warfare. Some will play CoD: WaW simply because it has 'Call of Duty' on the front. I just can't see Call of Duty 4 being the force it is now by the time Gears 2 come out. I think Halo 3 will survive the Gears onslaught, it has its Bungie fanboys and people who don't like Gears, and I'll the first to admit there is a few. However, Halo has stood the test of time. Gears of War is 4th despite being released in November 2006. I could be wrong, but I think this is the first sign of Call of Duty starting to crack. People are reaching 55 Golden cross and thinking "hmmmm, now what?" Basically, here's my prediction:

July- September

Halo 3 and Call of Duty 4 battle it out for Most Played Game on LIVE. Going back and forth every week.

September-October

Halo 3 becomes firmly the leader as the Call of Duty 4's fanbase starts to fade. Gears of War really close to CoD4 as people get excited about the sequel.

November-December

Gears of War 2 is released and goes straight to #1 till 2009. Halo 3 falls to second. Call of Duty: World at War is released and the CoD community is split. People don't like the new CoD game, 6/10 goes to Gears 2, 2/10 go to Halo 3 1/10 goes to CoD4.

So basically, CoD4's downfall will be it's sequel. Which, to be honest, I can't see being good. A lot of people I know dont want to play the WWII genre. So this game could fall flat on it's face.