I wanted to buy a LCD screen and was looking at either the 20 or 23". Now that these Imacs are out they are pretty tempting. I currently have a 12" powerbook 1.33ghz g4 so a g5 iMac would be a boost in speed. There is a price difference in the 20" monitor but not much in the 23". What does everyone think? Is there any reason not to just get the Imac?