These days, the only common factor to all the "Pro" Macbooks is the Aluminum Unibody.
So: Pro = Unibody
It`s just marketing, nothing more.
This is exactly right. Forget all the marketing or stupid car comparisons (why people insist on doing this is beyond me). Look at the specs.
OP: There are some questions you could answer that would help everyone give you some better recommendations. First, what are you using for your computer now? Why do you want to upgrade? Is there any way in which it doesn't meet your needs? You told us what apps you use, but you didn't mention if this is the machine you'll be using for work. If it is, I generally recommend you get the best you can afford so that a year from now you're not looking at upgrading again. That said, I may be biased since I'm a software developer and need the best performance I can get.