tangor - 1:24 pm on Jul 19, 2010 (gmt 0)
Last thing I ever change is the URI as that can lead to a start from zero, even with proper redirects... particularly if more than a handful are done at a time (less than 10).
edit: Was typing mine about the time Bill sent his!
About the only "trust" any search engine can give is the file name PLUS content. Content is supposed to change, update, modify... URIs usually do NOT. Unless there is something really seriously wrong with a filepath once indexed I would think long and hard about changing it.