Building a home entertainment system out of a laptop

[Juche]

I saw an ad for a Roku this morning and thought 'that looks pretty cool'.

http://www.netflix.com/NetflixReadyDevices?tb=details

You buy it for $99 and it lets you watch any of the 10,000 downloadable movies on netflix if you have a netflix subscription. So I would have a virtual library of 10,000 movies and TV shows to watch whenever I want.

So I figure that looks cool but as I think of buying it I realize I can probably just get a VGA to RCA/S-video adaptor to connect the laptop to the TV and a remote control that plugs into the USB on my laptop (which I hope would let me control programs like realplayer or windows media player) and use that instead and that setup would only cost $40-50 or so.

So that makes me think some more. I know I can get virtually any radio station on my laptop (its the only way I get air america here as no nearby station has it). And I can add an external harddrive via the USB and make it into a DVR. So maybe I should build a home entertainment center out of a laptop, a TV and some speakers. Doing so would let me get virtually any radio station, thousands of movies (via netflix), a DVR and TV broadcasts. Throw in a remote and wirelesss keyboard and I am set.

My concern is how do I set it up? I am new to this subject. I figure I need a

USB TV Tuner (I'd rather do a USB as I don't want to add cards to my laptop)
Remote
wireless keyboard and mouse (already have)
netflix subscription
VGA to RCA adaptor
External speakers (already have)
External hard drive to store DVR movies on (200GB or more)

Has anyone built one of these? How did it work out?