I have the MacBook Air, which I love, because I can stuff it in my work bag, no case needed and I can barely feel it.
On the other hand, I do nothing but use the net and email on my computer, or type papers. DH has the pro, which is much heavier. He uses it at home and then he bought another Mac, a teeny tiny thing that he keeps at work and uses when he travels because the Pro was a pain to lug around.