To answer the original question, yes filenames play a role in the google algo. How much? I'd say it's a small part, but every little bit helps. Google does see hypenated phrases as separate words, so
http://www.fuck-you-bitch.com/fuck-you-too/index.html would be better than
http://www.nokeywords.com/index.html.
As far as I can tell google ignores metadata, and focuses only on visible content. The url is visible so it is counted, although to no major extent. As far as pagerank check my sig to get some.