1.8 vs.2.0 ghz

The difference between the two is negligible and is more of a marketing device to help differentiate between the models and help justify the difference in price.

I seriously doubt that anyone would notice a difference.

Don't forget that you also get a SuperDrive for the $200 difference though.

gerald,
I'm not sure the average person can discern a 10% difference in processor speed. I still have both 450 and 400 MHz G3 PowerMacs, and without putting a stop watch to work, quite simply have never been able to tell the difference in their operations. I also have 1.42 and 1.25 dual processor G4's and found the same to be true with those.

However, with the iMac G5's you're looking at a significant difference in the fixed position video cards which is probably noticeable in gaming.

The 2GB is about 10% faster & includes a Super drive (DVD burner), if either of those isn't important to you, you would be better off spending the $200 difference on more ram.

Gerald,

While the differences in performance speed among the three (3) models of the iMac are small, you should look at the all the differences and the amount of money.

Start with the 17-inch 1.8 GHz model and then work your way up--in features and price.

The 20-inch, 2.0 GHz model costs $200 more. For that, you get 3 differences:

1. Ability to write DVDs. What is that worth? Well, the LaCie DVD±RW Drive, Design by F.A. Porsche 16x, FireWire costs $$119.

2. Faster 667 MHz frontside bus versus 600MHz which is worth $20 (assumed, for arguement's sake).

3. A 2.0GHz processor versus 1.8 which is worth $50 (assumed, for arguement's sake).

So, these 3 features are worth an extra $170. Apple integrates the DVD burner so you don't have an external drive and that is worth $30.
There is the $200 delta.
Conclusion: Buy the 2.0GHz and not the 1.8 GHz.

The next step up is the 20-inch montitor versus 17-inch for which Apple charges $300.
What you get is: 36% more viewable area. That is huge.
Compare these LCD monitor prices differences: SAMSUNG 20" 204T-B at $598 vs SAMSUNG 17" 740T at $342 (Source: www.mwave.com).
What you see is that Apple's $300 is quite reasonable.

Conclusion: Buy the 20-inch, 2.0 GHz iMac.

,dave

P.S. Don't forget to buy AppleCare.