Are iPhones burning up in the infernos of processor overtaxation, or is it all a big misunderstanding?

Apple hasn't ever been great at this whole "heat dissipation" thing, but some new developments in the supposed overheating iPhone scandal of 2009 have us wondering how widespread or reproducible these problems might be. Here are a few semi-facts we've managed to amass:
  • Somebody's white iPhone 3GS grew some ugly brown markings during heavy use.
  • A new development is saying that the discoloration came from a case (pictured), not from cooking the plastic.
  • More users than usual have been reporting an overheated iPhone error after the 3.0 update, but as Apple's support documentation points out, this could just be from the time of year (summer, in case you haven't been outside lately).
  • There isn't a large mass of evidence denoting a major fault to the 3GS, 3.0 or chintzy white leather cases.
So, all that said, what's been your experience?