Originally posted by: Captante
(1) Looks like you have that list about right although HDMI & DVI are equal & under most circumstances so are VGA & component ... in addition there are some situations where component/VGA can produce deeper color then HDMI/DVI.
(2) S-video is slightly better then RCA (composite) video but not much & yes its 100% fully worth it to make the switch, although how much difference you'll see depends on the video source. HDTV/DVD or Bluray requires component/HDMI so if you've been trying to view HD of any kind via S-video the difference will blow you away, SD-DVD will look quite a bit better & digital SDTV will look a bit better ... analog SDTV may not make much difference & neither will signals from a VCR if you still have one.
Component cables can be had at Walmart for a reasonable amount of money, but HDMI's will need to be ordered online unless you like getting ripped off.
Here is a good source for cheap & high quality cables: www.monoprice.com