I recently purchased a Macbook Pro 15" Unibody and my titanium steel watch is resting against the wrist rest. Which is the most reliable and affordable option to protect it from scratches on the wrist rest and the top and bottom of it's body.
A lot of people on here seem to like the Wrapsol... I'm wondering the same thing myself, since my new MBP is coming soon. I'm thinking either a Wrapsol, or maybe just the Moshi Palmguard. I just wish the Wrapsol had pieces for the front and sides of the MBP too.
Wrapsol did not work out for me. Very difficult to install, ruined the lid of my Macbook Pro due to the solution, and that wasn't covered by Applecare.
I say go with Invisible shield and get it installed for you. Or just be careful.