I would like to leevrage the experience from members of these forums and need some guidance toward an A/V buildout. I

have googled the heck and come to many forums (like these) all with differing opinions and my head is about to explode. I am not at all A/V saavy.

I recently received a new 37"Sharp Aquos HDTV (720p) from my uncle who upgraded to 52" and gave this 37" to me. I have always had CRT's and this new TV is pretty nice and new, even in non-HD.  I would like to look toward an HD/DVR solution at a low cost hopefully utilizing existing Vista ult MCE. My existing service is DirecTV, Hughes (non-HD) TIVO tuner purchased from Best Buy for $29 (3) years ago.

Options
1) Purchase DT HD DVR receiver and be done with it
 Upside
  One stop shopping, done
  Almost 100 channels HDTV
 Downside - very discouraging
  $299 one-time plus monthly receiver programming charges
  2 year contract conmmitment
2) Switch to Time Warner cable  - about the same monthly costs as DTV
 Upside
  No up front cost ($299 saved)
  No commitment (only month to month)
  Free install
 Downside
  only 32 HD channels
  I read lower HD quality than DTV (could not get answer from TWC)
  I read Fewer programming channels in packages (could not get answer from TWC)   

Hopefully I could leverage Windows Vista (Ultiate) MCE PC as a "replacement" for the HD/DVR receiver. i.e., the goal would be to have my windows MCE PC as the DVR HD receiver (for DTV or cable) and hook it up HDMI to the new Sharp Aquos.
 Unknown architecture (what tuner and audio card(s) are needed for interfaces)?
 Are all services offered by providers replaceable by MCE (DVR, HD, etc . . .)?

Rather than the standard RTFM response, it would really be helping me out to at least point me in the right direction.

You can't do HD with Cable or DirecTV with your existing PC. Actually there is now way of doing HD with DirecTV today.  You could do HD with cable if you bought a new computer with a CableCard tuner.

Edit: Almost forgot, you can use an HDHomerun to get at least your local broadcast channels in HD through cable.  Some people report getting other channels like ESPN & Discovery HD but that depends on you local cable company.

There is talk of a tuner from DirecTV that will allow HD but no dates yet.  Also most people here are predicting that the DirecTV solution will also require the purchase of a new computer with the tuner.