The 2.8ghz iMac still has a $100 low to medium end graphics card and that cannot be changed in any configuration. In fact, it actually got worse from the last generation to the this one for esthetic reason.
the 2.8ghz iMac still can hold only one hard drive that is not user replaceable
the 2.8ghz iMac still has a 8x slot loading notebook drive that is not only unbearably slow, but incompatible with camcorder DVDs.
Any attempt to correct these or other deficiencies results in a cable/external device nightmare on and below my desk.
I can't pull three grand out of thin air like some of you think I can. I'm also not going to be force into a professional system out of principle. I'm a desktop user, not George Lucas. I'm also not a lower end user with a lot of money to burn. Unfortunately those seem to be the only places Apple plays these days.