Not sure about toshiba but in general here are some things to consider
networking should be ok
IDE harddrive, cdrom, dvd, cdwriter, floppy should be no problem.
Printer, IR, usb, and com ports should be ok
mousepads, sticks, and track balls are ps/2, and very well supported
built in modem will probably not work, you may need a pccard modem
look here
http://www.linmodems.org/
normal video should not be a problem, 3D depends on the card support, check at XFree86.org for supported cards
r128 works good on my Dell laptop
Docking should work. I have seen no problems with external video
Most pccards will work
look here before buying one
http://www.linux-laptop.net/