He uses a cane all the time. But when he was fighting Dooku he didn't need it. He looked like a pinball in a pinball machine. Then he settles down and gets the cane again.
I guess when he fights he can use the force to propel him through the air instead of his legs. But maybe it's too draining to use the force all the time to hold himself upright when standing.
The cane is probably more of a symbol of stature. He is pretty much the most talented Jedi (except for Darth). I know a few old guys that walk with a cane just to look more debonair.
Duuuuuuuuude.
It's fairly obvious.
He's 800+ years in the prequel trilogy, so he can't just walk aroung like Anakin or Luke. He needs that cane. His style is Ataru because it's principle of using the force on your body to enhance it just fits right into an 800 year old guy's alley. Plus, he is really small, so it's easier for him to propel himself with the force.
Small, wise and a mighty fellow. If not the cane that he carried along, I wonder how he will look like without it. I love his quotes and his unusual speech pattern too.