As for dashes in a URL, it depends on whether you're constructing an URL for human typing or for search.

For example, I went to Google News, picked the top story, and looked at the story URLs. Some are opaque, but many look like this:

http://www.star-telegram.com/2011/07/02/3196643/exxon-mobil-...

If you're optimizing for search, the dash-separated words are very common. Google likes you even better if you make the most important thing first in the URL. E.g.:

http://www.sidereel.com/The_Big_Bang_Theory/season-4/episode...