Kyle,
Try hooking up the HDMI to your HDTV again, find the settings and turn the Sharpness setting all the way down to 0/ Nil. That should help if not resolve. It pretty much fixed the problem for me, and I returned the VGA adapter.
Jay,
try the same thing, I'm using a 40" Samsung via HDMI and it's decent when the sharpness is turned all the way down. Note: it still looks bad with the sharpness as low as 8-10, but at Zero, the HDTV stops "editing" the image. Note, that on my Samsung, EACH input's settings are individual, so it won't affect other HDMI inputs unless you change them.
Grekat,
That last bit should help you. It will vary with the model/make, but some HDTVs have indivudual memory for settings for each input. If that's the case, you'd just flip input from PC (via HDMI?) to your TV source (another HDMI, etc), without any issues. If your model HDTV can only retain one batch of settings, you might be stuck changing the sharpness when you switch to a different source, in order to get the best picture.