In general, any laptop will support Linux fine. Some specific features (wireless and video especially) may have issues, but these should not interfere with basic functionality.
Currently, laptops with the Intel® Centrino™ logo are the most likely to work perfectly under Linux. The Intel PRO/Wireless 2100 and 2200 802.11b/g wireless cards are supported by drivers released by Intel that are being integrated into the stock Linux kernel. Accelerated 3D support for the on-board video is provided by the DRI project and is included in recent releases of X.org and XFree86.
For more information about Linux and laptops, the following sites are good starting points.
Other information related to laptops can be found at the following sites:
See the PCMCIA/Cardbus section and the Linux PCMCIA HOWTO for more information on PCMCIA and Cardbus cards.