Yeah you can do all that stuff, the key to it all is the overlay controls in the display control panel. With ATI cards you can set video overlays to only go to the TV out, go to both the monitor and TV out, etc.
Read up on "Theatre Mode" in the driver docs for more info on it.
As for speakers I prefer Klipsch over any other PC speakers, but they're not cheap. You can get refurbs semi-cheap from their site at
http://store.klipsch.com though.