I purchased a 20 inch alum iMac in Nov 2007 for my wife. She loves it and it has worked perfectly.
20 inch, 2.4GHz, 500Gb disk, 4Gb memory, Iomega 500 Gb drive for Time Machine.
I purchased a 24 inch alum iMac in Jan 2008 for myself. I have not had one problem. The screen looks great, UT2004 plays VERY fast with ALL the goodies turned on, and there are no gradients or dead pixels on the lovely 24in screen. I love this machine and after being on the dark side (PC) since 1992 because the the corporate world I was involved in, I am finally back to the best side (MAC). in the last 25yrs I have had a Apple IIe, Mac II, Centris 650.
24 inch, 2.4 Gb, 500 Gb disk, 4 Gb memory, Iomega 500 Gb drive for TM.
Both were ordered with 1GB mem from Apple, and then ordered 4GB of memory (4GB for $95.00 from OWC).