The 1.83 is a much better value
I have promised myself a MacBook Pro, but I don't see the sense of ordering it by mail in my particular circumstance. So I am waiting for it to appear in the brick-and-mortar store. Meanwhile, I wanted to figure out whether to buy the 1.67 or the 1.83. The price difference appears to be $500, but the configurations are different.
The only way to do a proper cost comparison is to configure the 1.67 to be as similar to the 1.83 as possible. So I configured the 1.67 with 1GB of memory on one stick, just like the stock 1.83, and with a 100MB 5400 rpm drive, just like the stock 1.83.
The result: The 1.67 is $2,299 and the 1.83 is $2,499.
For $200, I'd get a faster CPU and 128MB of video memory.
So I conclude that if I'm going to add anything to the stock model, it's a better value to buy the 1.83.