I love my Macbook Pro 13". I really like the form factor: it's not too big and not too small. I would really like to have a Macbook Air, but unfortunately the small HD space and lack of an optical drive and firewire port are dealbreakers to me.
The dealbreaker for me with the MacBook Pro 13" is that you don't have the option of upgrading the display for a higher density display. The MacBook Airs come with this standard, and the larger MacBook Pros have an upgrade option available. Between having one of these displays on my MacBook Pro 15" and using a retina display on my iPhone and my iPad, I can't even stand to look at the display on the MacBook Pro 13" or the older iPads anymore.
