I was already planning on buying a new laptop later this summer, and was really torn between the Unibody MB and MBP. The larger, nicer screen and dedicated card were a big draw for me, but it was mostly the screen. The price drop, plus new features, and the drastically improved GPU (over my intel GMA950) means that I can now save quite a few bucks and just get the 13" MBP. Plus, from what I have seen, they dropped in the MacBook Air's LCD so the viewing angles are improved, as is the color.
I am already used to having a 13" screen, and if I were to get the 15" I would want the 9600m model, so it is now a choice between an incredibly powerful 13" MBP (compared to what I currently have) or a more powerful 15" for $800! more. Plus with Snow Leopard coming out not too long after I am planning on getting it (late summer, early fall. Hoping to score on the iPod Touch deal before it fades away) means that I will have a sweet little machine for the next 3 years or so.
Plus, 7:Q hours of battery life. Gizmodo's tests show 3.5 hours in their usage, but I get 2.5-3 hours on my existing battery, so I would probably be looking at something like 5 hours or more on the new one.