I like the way trackpad edge-scrolling allows you to "coast" (start scrolling with the edge of the trackpad, then release it, and the scrolling continues until you tap the trackpad again).

It's not enabled by default on Ubuntu 10.04, but here's how to turn it on (put it in a startup script):

xinput set-prop --type=float "AlpsPS/2 ALPS DualPoint TouchPad" "Synaptics Coasting Speed" 1