So you have a HDTV, but nothing to connect the HDMI port to? The most low cost device that can be connected to it is a DVD player with HDMI. Better yet, get an upscaling DVD player that uses all available lines on your fine HDTV. Most upscaling DVD players do 720p. The now shipping neodigits Helios H4000 is even able to upscale to full high definition resolution (1080p).
I had some doubts about the benefits of upscaling before reviewing the H4000. I was pleasantly surprised that it really makes a difference.