for picture quality is it better to use the hdmi cable recommended in the instruction booklet?

If your components (cable box, DVD player) support HDMI then you should use HDMI, if only because it's simpler -- a single cable does it all. Technically, it will produce a better image than component video cables (three wires, red/green/blue ends), but the difference will be minimal. HDMI or component video are the only options you can use in order to get high definition TV (HDTV).

Note: if your components support DVI, that will work too -- it's the same ad HDMI, but with a different connector and only does the video part. Get a DVI to HDMI cable for this connection.

If you use other cables (e.g. composite video, with a yellow plug, or S-Video, with a round connector) you will get a noticeably worse picture when displayed on your new HDTV.

Also, make sure you have HD service from your cable company and are tuned to HD channels. A recent survey showed that something like 1/3 of people who thought they were watching HDTV were not, either because they didn't have the special cable box and service required, or they did but were still tuned to the usual analog standard definition channels.

Hope this helps!