The good & bad of 20" iMacs
The previous reply is correct.
I bought a 2.4 GHz 20" iMac in October and have never had a freezing problem. Software Update didn't offer me the freezing fix when it became available. So you can assume the freezing problems have gone.
Complaints about the screen (in Apple's forums) go all the way back to the August release. Apple denies any problem on the phone and someone managed to get a candid comment from a Genius that they're cheap screens for home users, not professional use. Assume this problem is not going to be fixed. None of the 'media' have gone in to bat for us on this the way they did for the freezing issue - so apparently Apple can't be pressured on this. They'd have to replace every screen sold. It's not going to happen.
I have the colour (Aussie spelling) graduation problem - too dark at the top, OK in the middle and too faded at the bottom. There is no fix for this. I did an Expert Calibration and I'm happier with the screen, but it's not fixed. None of Apple's fixes have improved the situation.
In normal use, it's not a big deal - tiny text looks a bit scrappy if it's in the bottom third of the screen. If you're doing professional colour work, DON'T BUY one.
If it's at all possible, save up a little longer and get a 24", since having my problem, I've looked at a lot of display models and they're much better.
That said - I love my iMac and the glossy screen looks much better than the matte screens. They look dull and outdated to me. I have a friend who does Pro colour work on his (white) 20" iMac and he doesn't have the screen problem, so it's disappointing Apple went this way for the aluminum iMacs.
I like my screen better than the 23" cinema display, which IS suitable for Pros, but is not to my taste.
NOW, there are RUMOURS that the whole Apple line is getting an upgrade in January after the MacWorld. If you can wait that long, the screens MAY be improved. Given the angst created by these screens, it's possible Apple will quietly 'fix' the issue in the next release.
In an otherwise OUTSTANDING computer, the screen is a disappointment, but in some respects, an improvement on previous screens.
All the display models have this problem. If you want to see it, set the desktop to a mid -blue or green colour and look at the colour graduation from top to bottom. That's as bad as it gets. Then you can make a decision.
Save up for a 24", wait 'till MacWorld in January & research all over again, or buy now, forewarned.
Good Luck.
are those problems solved yet?