If your gonna be carrying it around a lot, dont go for the 17"... The huge screen and full keyboard are very nice, but the 17" laptops are monsters to lug around and usually get pretty lousy battery life. Just my 2 cents
I am a student and I have a 17" screen, and... the weight of the laptop is a pain, but I have lost inches off my waist line. I wouldn't give up those 2 inches, my battery life was about 1hour 45minutes. The only thing I use my desktop for is rendering.