The recent menu bar item count poll was quite popular, so this time, I thought I'd find out how many 'Other' System Preferences panels we all use. I asked the same question back in 2005, and the average was somewhere around three or four; it will be interesting to see if it's increased over time or not.
For the record, there are 10 on my main Mac (Apple Qmaster, DivX, Flip4Mac, GeekTool, Growl, MenuMeters, MercuryMover, teleport, TypeIt4Me, and Witch).
Mac OS X Hints
http://hints.macworld.com/article.php?story=20080606050342502