Here in germany we have a 14 day return policy for items ordered online. My first N900 (ordered from Nokia) had 2 or 3 annoying hotpixels, I called Nokia about getting it replaced - they refused since this is not covered by warrenty. Since I think that is not accaptable for a 600,- € device, I simply used my return policy and got my money back.
Second N900 came from Amazon with at least 7 hot / deadpixels - I used the Amazon exchange policy (they'll send you a new device, you'll send in your old one then), though they said even those 7 pixels still aren't warrenty covered, they exchanged it.

My third device, the Amazon replacement device, has a dead pixel. I finally kept it because I don't want to know what my fourth device would've looked like.
Either I am unlucky or Nokia has/had a serious problem with their displays. No smartphone I ever ordered had a single problem with dead/hot pixels. On the N900 it almost looks like a built-in feature. For such an expensive device, this appears to me like a bad quality assurance.