TrustedReviews have looked at the Apple iMac 20in.
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Apple iMac 20in Review
Apple's 20in iMac lives up to the hype. It's a lovely machine to look at and to use, and even in its base spec it's fast enough for the average person and very good value too. In a nutshell, it's the best desktop computer around, though you might want to wait for Leopard, the next version of MacOSX to be released before going for it.
Apple iMac 20in Review