I actually really enjoyed Halo single player campaigns.
As far as Chaos Theory, the only two real options if you enjoy online versus mode are Xbox and PC - And I despise PC control system for Chaos Theory, just feels so much more natural with a controller.
Thats why I left that one on the list

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I am looking forward to seeing what the Revolution and the PS3 have to offer, but neither interest me as much from past experience as the Xbox console. I use to be very, very big into PS2 and wouldn't give Xbox a chance. Something changed me, gave it a shot, and simply enjoy it more overall at this point in time. We'll see how it all plays out when all the sequals release to their respective systems, but so far I'm just more into Xbox

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I know Halo seems to be a love it or hate it thing though, I'm actually more looking forward to the next Halo's singleplayer than I am multiplayer though. I really like the story, the gameplay, and the feel of the universe.