The Protection lowdown: discoloration, etc?

[Trepex]

Hey folks,

I've searched-for/read-through dozens of threads here about various mac protection options and I guess I'm looking for the lowdown in terms of what's actually necessary.

1. How bad is the risk of discoloration of the palm rests on the macbook pros?
2. How about the risk to the screen from the keyboard when the laptop is closed?

I'm not super concerned about scratches on the outside of the case. I'm very careful with my things and I'm not even worried about the odd scratch. I'll likely get a neoprene case for when it's going to be in my bag being transported or sitting around somewhere. The thought of add a pound of plastic to my MBP isn't all that appealing, especially with all the people saying how the seethru case itself can actually cause scratches!