Don't get that pdair case. I was considering it myself but I read a review on this forum where the belt clip gave way after a few weeks. Also the case covers the N900's bezel so you can't swipe as easily.

I personally just use a screen protector and a rubber case I found off ebay, the back of the case isn't staying on as strongly but I only paid 5 dollars for the whole case anyway. I then put it in my pocket (I don't wear jeans, i don't like how it makes taking out my wallet a struggle). Though on the other hand it would be a great way to stop yourself from spending money.