New Machine;New Questions

So two days ago I made the move from my PBG4 to a new 2.4 GHz black MacBook. I must say that the speed increase is awesome (which is quite obvious when going from a four year old machine). I decided that, as much as I did like the alu casing of the MBP, my computer usage does not require the jump in cost. Since this is my first plastic coated Mac, I do have a few questions.
I see that people are having problems with their casing cracking at the bottom of the left, and especially the right, palm pad. Has anyone tracked down a probable cause for this? I am assuming that it is people being careless when closing the lid and having the magnets pull the case together too quickly?
Also, to my fellow black MB carriers. I am sure many of you, just like myself, are probably a tad bit OCD. In an attempt to keep my computer pristine, and slightly due to ergonomics, I purchased a Griffin Elevator and BT keyboard. I feel that this will keep me from getting the palm rests/keyboard all grimy. Having the BT mouse I think that my trackpad is safe, too. But, I will be using the computer away from the home base, so does anyone have any proven cleaning methods to keep the black MB looking new? Should I just use the iKlear on the keyboard/palm rests? I don't want to discolor/make the computer look overly worn out either.
Any input would be appreciated