This thread is hilarious.
In most cases, dev teams have licenses to use multiple packages on any given project. Sometimes all modeling is done using one and animation done using another. It can also be up to personal preference of whoever is doing the work since it is extremely easy to go between programs. Maya and Max are perfect examples of this thanks to the fbx exporter.
It doesn't matter which you use. In the end, it's the engine which will determine the final quality/look of your game, not the 3d app you are using to make the assets with.
Having said all that, I enjoy Maya more than Max although I am profficient with both of them, and XSI as well. And where XSI is concerned, well... LOL. Its an awesome program, and IMO out-does both max and maya put together. But only a handful of dev teams use it.
And the people posting crap like "Capcom uses XSI" have no idea what they are talking about. A company as large as Crapcom has multiple licenses for different products. I'm sure XSI is one of them, but they aren't limited to using just that.