Although I can't speak as to setting yourself up with a laptop (as I only have a desktop), I was looking for a setup exactly as described - using the TV as a monitor on which I can watch media, browse, play games, and whatnot - while still maintaining a secondary monitor on which to perform more meticulous tasks that I can't see on the TV.
My desktop is setup with a dual DVI-out graphics card (Nvidia GTS 250 to be exact), with one DVI to HDMI running to the television, and a second 15' DVI to DVI running to a monitor which I have on a station next to my sofa. I'm a little obsessive, and as such have a Logitech Revolution wireless keyboard/mouse combo which works fantastically for controlling things from around my apartment, and a wired keyboard/mouse for when I'm stationary.
Since DVI to HDMI doesn't support sound, I routed sound to my stereo receiver via R/L audio cables and an adapter - this could support up to as many speakers as your sound card/receiver can support.
On the software/OS end of things I'm running Win7, with the secondary monitor as primary. Furthermore, you can support as many monitors as you have ports on your graphics card(s). 2 graphics cards = 4 monitors :O
Hope this helps a bit - I've used this setup for over 8 months now and it is FANTASTIC!
