XM

I'm at the point now where I can't listen to anything else in the car but Sirius.  And if I'm stuck in our 1 car that doesn't have it, I usually go to the Public Stations at the bottom of the FM dial.
Look, it's simple, terrestial radio play the same songs over and over.  There is no variety.  And then there's the commercials.

No future car of mine will not have XM.  The only problem with it is that there's too much to digest.  But a small price for those of us hungry for variety.