Despite always using a screen protector, I developed a fairly large (40 pixels?) spot on a Treo 600 which was under warranty. T-Mobile didn't give me a hard time about the warranty and swapped it out at no charge. The new one is still under warranty, but now I have a small white/yellow spot and a small orange line. I hope to replace it once again and then sell the new one before it produces a new spot, but I have a question:

Do Treo 650s also have problems developing these spots, or is the problem mostly limited to 600s? My understanding is that these spots are often due to moisture, and I sweat a fair amount. If 650s also develop these spots, then what case(s) and/or screen protectors would you recommend to maximally shield the screen from moisture?

TIA ...