i'm considering buying a 12" ibook.
i would use the pc mainly as a background support for my home pc, just to run some photoshop and some cad, but most of all, for office appz and internet. i thought of the 12" model because of it's small dimensions and low weight, cause i'm always "on the run" and tired of heavy weights on my back.
12" is perfect for those that simply need to be mobile while still getting the same performance. I think the 12" iBook is kind of cute looking, so if you don't mind appearing cute then all the more power to ya'!
12" all the way. I'm on my second 12" - first was an iBook, second was the powerbook, and I wouldn't dream of going bigger unless it was my only machine. You just can't beat the portability and form factor, and the screen is so good you really don't miss it.