I've had my Xbox 360 for about 2 1/2 years now and never once got the RRoD.  I still haven't but it looks like I'm going to have to replace it anyways.  I was playing some Left 4 Dead with my brother yesterday when suddenly the picture started flipping out.  We restarted the console and it happened again about half an hour later.  It seems to me like the problem's with the GPU.  Here's a video I took today of it.