Elaboration:
I have a clear iSkin on my 17". Love it.
- Keeps keyboard clean
- Easily washed
- Quieter typing
- Softer typing (feels softer)
- Backlit keys still shine through
One shortcoming: My wife's 15" PBG4 has an older iSkin that is contoured slightly different than my mine. Over two years, smudges in the shape of the keys have started to show up on her screen from touching the iSkin while the kid is closed. These easily wipe off, and could probably be avoided altogether with regular cleaning of the iSkin. This problem has not occurred on my MBP with the newer iSkin.
Another company to consider is zCover, which I have on my Apple Wireless Keyboard.
If there is an Apple Store nearby, I'm sure they'd let you open an iSkin or zCover package and test it out on one of their laptops.
While you're buying accessories, other cool things to consider are a Wrist Rug and Track Pad Film from
POWER SUPPORT as well as a
Speck Hard Shell Case or, if you're "into" leather, a
U-Suit.