best screen protector glare filter

The screen is covered with glass, which protects it. The glass doesn't need protection, any more than your home's window glass needs protection. If you don't worry about protecting your windows, don't worry about protecting the glass covering your MBP's display.

As far as reducing glare is concerned, there is nothing on the market to do that that won't reduce the brightness, sharpness and contrast of what you see. All such products are plastic films that may be difficult to apply without trapping dust and air bubbles. If you wanted a nonglare screen, you should have bought one. There's no other good way to get one now.

I Googled "macbook glare filter" and found this at: http://store.apple.com/fi-business/product/TV685ZM/A

Contour 15" Privacy Filter/Anti Glare film for MacBook Pro

Reduce unwanted glare and shield your MacBook Pro screen from prying eyes with the Contour Privacy Filter and Anti Glare film.

* Anti-Glare, Anti-Reflection
* Prevents unwanted viewing
* Protects against scratches and abrasions
* Extremely lightweight and durable

That Contour one doesn't seem to be available in the US, but how about this one:

http://www.etechparts.com/ProductDetails.asp?ProductCode=822-2279

Macintosh MacBook Pro 15.4" Unibody UniClearCal AG (anti-glare) films greatly improve the viewability of glossy glass displays when used in brightly lit or outdoor environments. ClearCal films combine a tempered 2-mil matte finished, anti-reflection layer, permanently laminated to a 3-mil flexible transparent base. A blemish-healing siliconized adhesive provides an optically-correct, yet easily removable bond that conceals existing surface defects like abrasions and scratches. The siliconized adhesive is permanently bonded to the base layer and will never leave any residue behind if later removed.