Thanks for the advice!
I'd go to a Sony store or Borders, but there's nothing of the sort near where I live. And the local Target is useless.
It does seem as if the 505 is the best choice currently available. I'm going to ponder it over the weekend, but unless someone points out a much better alternative which I haven't noticed yet, or which is due out soon, I think I'll be buying one.
Many thanks for the assistance!