I have a Late 2009 27" iMac thats been a work horse. Lately I've noticed screen issues ("marching ants" vertically across the screen every couple inches, more noticeable on dark backgrounds) and like a soft watermark across the screen? Again more noticeable on dark backgrounds. Anyways, I downloaded iStat and have been paying attention to the temps, after speaking to several people I've been told these are way too high, but I really have no idea. Any input it very appreciated. Its super hot to the touch as well.