I'm going to buck the trend and say get the 13"MBP. you get all of the ports that the 15" has, you have a powerful GPU (9400m), smaller form factor and lighter weight.
Back in October when the differences were more pronounced (mbp = better screen, fw) I agonized over the decision. While I have no regrets, the deciding factors for me were the screen and GPU. After the fact, I find myself in the 9400m most of the time.
Like I said, I have no buyers remorse but knowing what I know now, I'd probably get the 13" model.
While I'm truly enthralled by the MBA, I don't think its cut out for a primary machine, due to the sacrifices made because of its form factor and now that the 13" MBP has the same screen as the MBA, it makes even less sense to spend more and get less.