Honestly though, since you are going to be paying $6/month regardless of which model you get, & since you already have HD access on your account, you should just go ahead & spend a little extra $$$ & get at least an HD receiver of some kind.  (preferably an H24, but at least any H2x series receiver)
You ARE going to get stuck with another 2-year contract regardless of which model you activate, so you may as well be ready if you ever get an HDTV in your bedroom.  I think if you settle for an SD receiver, you will NOT be happy with it after having that HR24 on your other TV.  
Also, for another $3/month, by having an HD receiver, you could then have MRV so you could watch DVR'd shows on your bedroom TV.  (MRV ONLY works on HD receivers)