Get BOTH !!!
I have a netbook and mobile wireless that allows me to do work while being driven down hwy 1 (awesome view) THEN
Have a large laptop 17" dual core for doing work in the hotel at night.
IF, you aredoing lots of traveling and need to check NOT work on your campaigns I can not say enough good things about ASUS new dual-core netbook from amazon/bestbuy/ etc/ They JUST released JAN 10 th 2010. It saved my $$$$$ while at ASW2010 being able to check and tweak campaigns while 2 blocks from my hotel.
I did miss having a large screen and faster processor for work at night, BUT damn glad I was not lugging that on my shoulder in the confernce or the airport.
IMHO
p.s. HP & ACER suck.. Toshiba and ASUS are tested best betbook.