I'm using it not that often because one of the first addons to my N900 was the "Touch screen pointer" from Krusell, a strap with a litlle stylus on. This way it can never get lost and it's faster to use than the stylus. But it's only useful for short actions, some fast swipes and touches and not for longer working because the stylus istself is quite small. But the most useful gadget on my gadget
I use the stylus whenever I need to copy text on a webpage. Slide the stylus from the left side of screen, move curser to start of text, hold shift key on keyboard and move curser to the start of the text I wish to copy. Cntrl+C and Bob's yer uncle.
I lost mine about a year ago. In the beginning I missed it a lot. Thought about buying new styluses. But now I am used to it. Maemo really works well without stylus. But sometimes with repetitive tasks a stylus is easier.
I lost mine a couple of months ago, and I had already lost the spares I bought from eBay while moving house. I miss it occasionally, but a combination of zoom (in microB) or a biro/pencil/twig/chopstick (anything else) means I'm not that sad.