17" PowerBook here.
I have used ThinkPads, Dell laptops and a few other brands. This PowerBook is the easiest to use. I have Office Applications for the Mac. Use Safari as the browser and iChat to talk to AIM friends.
PhotoShop Elements came with my scanner. (That's the scanner with the cable I just plugged into the USB port. I don't know what that other person was talking about earlier.) I have a printer, a scanner, a digital camera and a high end camcorder. All just plug in and allow me to very easily transfer data. Creating DVDs using iDVD is easy and fun.
I go to visit family and it is no effort at all to log in wirelessly.
Full Disclosure: I bought my first PowerBook last summer. The drive was dead five days after I bought the machine. I took it to the Apple store. They didn't replace the drive. They gave me a brand new PowerBook.
I would highly recommend the 17". As others have said, having this much real estate and being able to have so much open and visible at the same time is sweet.
"I would highly recommend the 17". "
No kidding. 17" seems almost as good as a 21" monitor.