data acquisition board for laptop (Linux)

Hello everyone,
After having toyed with Arduino for a few weeks (really fun) and learned a few things regarding interfacing with leds, relays, buttons, servos, etc, I am now thinking along the lines of getting a crappy laptop, sit it on top of a two-wheel robot, and let it take control of the whole thing.
What I need is, I reckon, some sort of data acquisition device (analog-digital and i/o) to sense and control leds, accelerometers, bumpers, sonars, etc. I need advice about what kind of device to look for considering:

  1. it will be hooked to a laptop, so PCI boards are a no-no.
  2. it must work with Linux (Ubuntu flavour).
  3. it would be perfect to have a pwm controller built-in, to make motor control simpler.

Anyone has any suggestion?
Thanks in advance!


Why not just built it with an arduino? It would meet all of your requirements.