For the sake of full disclosure: yes, I have a Sitemeter on this blog. It's the free version, which means I can't see anyone's full IP address (just the first three numbers). I can, however, see your location, your ISP, a crappy estimate of your latitude & longitude, what page you came from, and what page you exited to (sometimes; this last one seems to be borked).
I have it on the "medium" privacy settings, which means that all those details are not visible to members of the public, but that certain stats may be given out to indexing sites -- the textbook example is giving out the hit count to a service that ranks sites by number of visits.
I'm not all that interested in most of the information that Sitemeter collects. I mostly have it as a hit counter, not anything fancier. I do get a kick out of seeing what random cities people are visiting from, or what random Google search terms bring me up in the results. It's rather annoying that Sitemeter's privacy options are pretty much all-or-nothing: I can't allow members of the public to see, e.g., just the Google search terms or just the geographic locations, without giving them everything, including partial IP addresses. Grr.
But at some point I think I'll compile a list of the more interesting Google search terms that bring this blog up. Might be amusing.