The best replacement for touchpad is mouse.

The best alternatives to touchpad are rated as following:
★★★★★  mouse
★★  trackball
★★  ipad 2
★  playbook
★  clickpad
★  pointing stick
★  trackpad
★  xoom
★  blackberry playbook
★  touch screen
★  motorola xoom
  touchscreen
  trackball wireless keyboard
  trackpoint
  toshiba thrive
  9
  rowmote
  vizio tablet
  external mouse
  mobile mouse
  synaptics

Your alternative for touchpad is not listed? Suggest!
Speaking about touchpad, one probably shouldn't forget about keyboard.

Other search terms related to touchpad and their ratings are:
★★★★★ keyboard
★ vertical scroll
You have in mind a companion for touchpad and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of touchpad in all years. Click on graph for more.
touchpad
mouse
trackball