I love using the Optimoz mouse gestures extension for Firefox: hold down the right-mouse button and drag left or right to move backwards or forwards in your browsing history. There are also other motions for other actions, but back and forward are about 99% of my usage.
This is also built into Opera as standard.
Well, as you can see in this screenshot of the DS Browser, it supports the same thing! Hold down the left should button and drag the stylus left or right across the screen to go back or forward. Excellent! I’m really pleased to see that the browser will make use of the touchscreen even for basic things like navigation. I don’t remember my Sony Clié supporting anything like this and it really will make such a difference to the overall usability and experience of using the web on a small device.