In Longhorn MS is looking to add some laptop-specific features designed to make portable machines easy to use as consumer devices such as portable DVD players. They are also looking to add a separate UI that could be “instantly booted up“ to play movies, music, etc. – hence getting you the the experience more comparable to using consumer electronics devices.
For someone like me who is mostly on the road, this would be good, if I can cut down to one “device” (i.e. the laptop) along with the chargers, wires, etc that I carry – my shoulders would certainly thank me.