I have to agree with the other party that said the CPU power in the MB 2.4 is the same as the low end MBP at 2.4 GHz and that is what is important for you. At the same time, I think it comes down to preference. The MBP has a 15.4" widescreen and is difficult to use easily in an airplane seat but easy to use at a desk or table in the library. However, the MB weighs less and is much better for portability.
One more consideration. If you want ultimate portability, buy a MBA 2.0. The high-end MBA is a 1.86 GHz. Although the CPU is a little slower than the MB, it has double the L2 cache. The MBA 2.0 is a very capable Mac. It is the ultimate in portability and is the coolest Mac ever in my opinion.
And, I guess on the other end of the spectrum is the 17" MBP. Not great for portability, but the display is amazing and the battery life lasts up to eight hours, according to Apple.
Finally, with the smaller displays you can buy an external display and they become instant desktops. All of the new MB, MBA, and MBPs have mini display ports and can drive a 30" external display.
All comes down to desired portability in my mind. All of them are capable Macs for your needs. Best wishes with your new Mac.