Apple had various issues with their hardware over last few years. I remember that lot of people had problems with first "Titanium" laptops, they were literally falling apart (case problems, display problems, HDD etc.).
New iMac line also has various issues, especially 24" model. I was considering buying that model recently, but I gave up. I didn't like it's almost non-existent upgrade options and screen quality, but later I found it had more serious issues. For example, 24" display is way too bright, even if you turn the brightness setting at the lowest level. However, if you turn down the brightness level, suddenly iMac starts to emit humming noise, and the lower you go the hum is louder.
I think those are serious issues for such expensive computer (I know that new iMac's are competitively priced, but you can still get PC with faster processor, faster GPU, more memory, more HDD space and faster drives, and better display for LESS money, not to mention upgrade options, so they are still expensive IMHO). You end up paying for Mac OS X, and although to certain extent it has sense, since OS X has many advantages over other operating systems, combined with quality issues iMac line has at the moment I think it's not as good option as it seems at first glance, unfortunately.
I just can't understand how could they make such bad move with the 24" iMac screen.