So, I am working my way - albeit extremely slowly - towards a media center PC. We have the TV, thanks to a great Christmas gift from our in-laws. A month or so ago, I got a wireless N router - not specifically for the media center project, but it will be nice if I do much streaming.
Last week I loaded up XBMC on my laptop to try it out as the basis for a media center set up. XBMC is a free media center application that has a nice, customizable interface that looks good on a TV.
Today I got an HDMI cable and tried running XBMC on my laptop and connecting it via HDMI to the TV: it looks great, even with streaming stuff - I was pleasantly surprised. All I need now is to rebuild the older PC I have, get a quiet, beefy power supply and a video card with HDMI out. A wireless keyboard should round it out, as pretty much all the XBMC navigation stuff can be done via keyboard.
It's a nice project, I'm not under any pressure as it's purely for my amusement; I have a fair bit of the stuff already available, and the pieces I do need are not really expensive. Sweet!