I love my 12" Macbook, I'm using it to write this reply, but goodness is the keyboard awful. I have a can of compressed air at hand at all times to blast the keys when they get stuck.

I'm about to (if the shipping notification is anything to go by) upgrade to a 14" MBP but I really hope Apple release something in this size again. It's such a pleasant laptop to use; I even work on my (2D) C++ video game on it.