Hi there Pam!
I am an avid Mac user, and do most of my work on a Mac. If portability is a key feature, I would suggest a 13" MacBook Pro, which is what I use. The battery life is around 10 hours at best (depending on what processes/applications you run), and is considerably lighter than the 17". They are quite durable with the aluminum unibody, and very versatile.
You might even consider one of the MacBook Air models, but they have less storage space and the processor is a little slower.
And just as Amanda said, if you are not familiar with the Mac OS, there will be a learning curve, but I assure you that the ease of use is rather amazing. I have both Mac and PC systems, and I prefer the Mac because of its speed, quick and easy navigation, and processing power.
Hmm.... Maybe I should get a job at the Apple store, LOL!
Best of luck to you! Let us know whichever system you choose works out!