Hoople - 4:13 pm on Mar 15, 2010 (gmt 0)
I have only used 301's mostly to show Bing the correct page. The MSN bot often comes looking for pages long gone (2007-2008) due to a succession of several rename happy previous webmasters.
When I took over this one site I left the naming as is, adding the 301's to address 404 errors only. The backlinks were notified and most changed to the current site page, a very small percentage of link sources never responded or changed.
FWIW I do have example.com wild card redirected to www.example.com