I got a new MBP last week. The plastic wrap is definitely not suitable for long term use. It's got the adhesion of a post-it and thickness of a ziplock bag.
I'm also a big fan of invisible shield. I have full body versions on my ipod touch and Canon digicam. I've also used screen versions for cameras and a blackberry. Excellent product.
However, I wouldn't consider it for the MBP. With such a forgiving finish and relatively wide expanses, I don't see it as a good match. But I'm curious to hear form others who have gone that route with laptops. I AM thinking about doing something to the glossy screen. That's really distracting.