I need to decide in a few days between the MP alum and the MBP alum. My concern is: How tough will it be to use on the plane? How portable will it be, much difference than the MB? I would use it sitting on the couch, at starbucks and in hospitals....mainly it would be at home but i have a trip once or so per week.
Doesn't matter if you're in a hospital --- as employee, patient, or visitor --- because you'll have no problem using it in any of those places. I don't see why you would.

I've used it at a hospital, and I was fine. I have my own desk though.....
Starbucks? No problem, but if you're sitting at one of those small round tables you'd typically find at cafés, it will take up most of the width of the table. That means it may be difficult to keep your coffee beside your laptop. If you're sitting at a mid-sized table or large table, then you're OK. Personally, I don't keep my coffee beside my laptop anyway because I'm afraid of tipping it and spilling it. Instead, my coffee is sitting behind my laptop, but at the side so that I can still see it. In its place, I have a pen and little notebook for writing down notes. With a 15" MBP, it won't always be possible to do this. I'd have to make sure I'm not sitting at a small table. A 13" MB is just right for pretty much any table you'd find at a Starbucks. I've been to Starbucks plenty of times with my MB. I may even do so later today.
On an airplane? You'd have trouble. The 13" MB is the best Mac for use on an airplane. It's even better than my old 12" PowerBook because it isn't as tall, and so I can tilt the screen back enough to see the screen, as long as the typical passenger is sitting in front of me (reclining the seat by a typical amount). I've flown hundreds of times with my laptop, on a dozen airlines or so, and so I have some idea.

The 15" MBP is too tall. You can definitely use it on an airplane, but it'll definitely be awkward.
I don't know about 1st or Business class though.