Alltek Vision External TV Box w/Remote
It has a built-in switcher so you can hook it up to your computer monitor without having to switch cords for each input. It takes Component and S-Video inputs, so it may be able to handle high-res inputs, like 1080i, etc. No HDTV tuner though, so who knows.
Otherwise if you have an XBox the
X2VGA comes highly recommended. Unfortunately it can't display DVDs on a VGA monitor properly since Microsoft disabled 480p for DVD playback on the XBox.