I use the stylus for Xjournal. It's easier than bringing a notepad during a townhall session or meeting. I can reconsile the scribbles afterwards.

I also use the stylus for Mypaint.

Sometimes, just to move shortcuts or widgets that require (more) precise movements.

Overall, yes, I do use the stylus rather often, and would be at a loss without it.

Edit: Not forgetting to play Angry Birds and Airport.