Do You have a preference or screen size?
Capacitive, resistive, active digitizer (or do You care about a touch screen?)
Is battery life important?
There's a big difference between a 17" laptop, a netbook, and a convertible.
I use a Fujitsu Lifebook T5010. I got it off FleaBay, and upgraded it to a 1TB HDD, 8GB RAM, and 2 sets of batteries (6 hours per set) all for about $300.