I use the ones from clearprotector.com and recommend them highly. They are basically invisible and crystal clear and do not interfere with the screen sensitivity. I've also used zagg on older phones, and the clearprotector are basically identical if not better.

ultra clear looks like it's not even on the phone when you put it on correctly ... the anti glare reduces the quality of the screen IMO ... besides the n900 is not bad with glares ... and i hated the zagg because they are rubbery on the screen and i hate it IMO ... i bought calrivue and used it ever since ...

http://www.protectionfilms24.com/art...900-28210.html

This one has been great for me. Nice solid crystal clear surface. No drag when using a finger or stylus. Very responsive too considering how tough it is.

clarivue is great. I tried the lexpro (I think that was the name) and it didn't last very long.

clarivue is the best , i have been using them for 6 months still no scratches !

you get two of them for 12 bucks , use the code clear123 to get 10% off .

I got the ultra clear one and it works great , give it a try