I'd also go with a laptop. For long term use, I prefer a wireless external keyboard/mouse and a 24" HD monitor for comfort. To get more bang for your buck, consider looking into Dell's factory outlet. They have both new and refurbished units that are much cheaper than regular retail.
We've gotten 2 refurbished units from them and would do it again. This typically means the unit failed final testing and it had to circle back for repairs - not that someone used it and returned it.
http://www.dell.com/us/dfh/p/?cs=22&c=us&l=en&s=dfh&~ck=mn&redirect=1