I have used a couple different one's:
-The Boxwave anti-glare is nice, if you take the time to put it on right, you wont even notice it. They are much much better than the stock=crap protector that comes with it. I used one for about a year before I decided to replace it.
Pricey though, about $13 for one. and they dont have the mogul on there site... but I think the 8525 is the same sized screen..
-Another that I am currently using is the "Jazz Screen Protector." I think they are from china so they take a little longer to recieve, but they are only about $8 bucks, and you get 3 of them. I'd say they are equivalent to the Boxwaves, but a lot cheaper. You can find them on Ebay, search for "jazz screen protector 6700" (no quotes). I dont believe they list them for the the 6800 so I just ordered the one for the 6700.
The Jazz Protectors, I believe (dont quote me
) are from the same company that makes the Exim screen protectors. I've read these are good also, but more expensive.
So, I recommend The Jazz Screen protectors because they have good clarity, and toughness and seem to be a good alternative to the high dollar boxwave's or invisibleSHIELD's.
Also If you want some good tips as to applying these things, search "screen protector tips" in the aximsite.com forums, 3/4 down the search page is a good thread.