The problem is each model is missing something.
12" isn't 1 Ghz, memory ceiling, not easy to hookup large screen, no firewire 800, no lighted keyboard, no PCMIA slot. I consider it a faster ibook.
15" not updated with the new stuff(bluetooth,firewire, airport extreme)
17" a little to big, high cost.
If they update the 15 that will be the one for me.