All of them. It takes a cablecard. Whatever channel package you are subscribed to, you will get.
If the channels you watch are on the FIOS app, then I say you are good. I don't ever watch live TV, so I use media center (which runs directly on the xbox extender).
There is also an app for istuff that you can watch live TV, and they have recently added a DLNA server which will open up a number of devices (PS3 for instance) to watch live or stream media. I know VZ has the app now too, so there is choice which is a good thing.