if you want to sell your device in the future you will need to protect the screen
Zagg Invisible Shield 'full body' went on my n900 when i first got the device and its in mint condition because of it
but i also have a galaxy tab and an ipad, and dont have anything on their screens, because they dont go in and out of my pocket everyday

Some of the air bubbles are not really air bubbles. Most of the time, there is dust or lint stuck beneath the screen protector. Get a scotch tape and gently take out the dust or lint on the screen before applying the screen protector.

I've had better luck applying the screen protector in my garage (which has no air conditioning and normally goes days without anyone entering it). Probably any place with limited air movement, so that dust can settle out of the air, would be useful for this sort of task...

I've had screen protectors on for a year but then had some issues with the screen not responding to touches, when I removed the protector the issues vanished. I've now decided to go permanently 'naked' as I've had my N900 for over a year now and I expect to keep it another year at least as my main phone - If I get a few scratches and decide to keep it a third year, I'll buy a new front screen! and...I've cut my nails :-)

Dan

p.s I've found a big improvement in the screens clarity and responsiveness without the protector.

Tried to put on a cheap screen protector. Turned out that the patience I have while learning new guitar tricks or fiddling with computers was not apparent while trying to apply the protector. So I wasted one of them and the other one is still in the Nokia box.

I am really careful not to scratch it, though, and I suppose I would be less careful if I wouldn't have to pay so much attention to it.

i have a invisibleshield from zagg. it's the best and a screenprotector ist a must. the screen glass is not very scratch proof.

I use the CP-321, my N900 looks the same as the day I bought it.

I have been using a screen protector since day one, I got it free with a protective case from eBay and I've had no problems with it. I would not want to use my n900 without one, it's too valuable and vulnerable and heavily used for me to take chance.

I'm also interested in getting one of the privacy screen protectors, the ones using the 3M microblade technology. I did actually get a cheap one from eBay but it's orientated incorrectly, someone sitting beside me on the train would be able to see my screen just fine but someone sitting above me wouldn't. I assume the manufacturer didn't realise that the n900 is used almost exclusivly with landscape orientation. If anyone here has found a correctly orientated privacy protector then I'd appreciate them posting the details here.

On a related note, it took me a while to find a decent protective case that was usable. I tried a soft rubber case and a hard plastic case and found major issues with them both. I now have a 'gel' case which I'm very happy with. It's worth noting that the gel case has an integral screen protector, it's transparent and the portion covering the screen is much thinner than the rest of the case. It's thin enough for touch to work although I found the accuracy suffered, that may be because my conventional adhsive screen protector was still installed under it. I cut the screen section out of the case with a scalpel but it may be an option for some people and as a case it's wonderful.

Screen protectors are all well and good, but they won't prevent you getting a nice dent in the screen like on my device!

When you do scratch your screen you will wish you had used a screen protector.

I've been using a Vikuiti™ screen protector DQC160 on my n900 for over a year now and the screenprotector has some minor scratches and one small deeper scratch.

I will be trying the Martin Fields one next...

BTW, there have been numerous interesting threads before about screen protectors so if you want to read about them, just search