Search here:
1] The Linux Compatible laptop list http://www.linuxcompatible.org/compatlistcat44.html
2] The database at Phoronix www.phoronix.com/lch/
A friend of mine says that Hewlett Packard notebooks are generally compatible with gnu/linux.
Beware of buying 'blind'. You might end up with a laptop where the webcam and the card reader will not work. That can be a piss-off, though the rest of the hardware will work fine.