What should I wear or not wear when on-camera?

When you look good, the public will be more receptive to your message and see you as an authority on the message you deliver.
Some clothing will look good to the camera and some will distract.
The worst on-camera offender - white clothes.
Wear neutral colors and try to avoid wearing flashy jewellery.
Try to look classy and friendly.

Black or white is not recommended due to white balance and contrast levels.
Business casual is preferred.

Avoid pure white or black.
Go with neutral colors or pastels.
The camera will boost the contrast.
White on television can blind the viewer.
Black and navy will look as dark as midnight.
Stick to more muted colors.
Also, don't wear shirts with logos.
Wear comfortable cloths and shoes.

Business casual.
Nothing too garish or distracting.
That will take the focus away from what you are saying to what you are wearing, unless what you are wearing is what you want the focus to be on :)

Hello Peggy Traboulsi Chamoun, Greetings! Depending upon the Event you should Decide what to wear or not wear.
Business Casual is preferred if you are at Work / Office / Meetings.

Dress appropriately.
The most common dress code is business casual.
If you are not required to follow a certain dress code, wear what makes you feel comfortable and you think would be appropriate to go on-camera.
Always look smart and classy; avoid very bright colors and opt for ones that are more camera-friendly.

These days background colour WHITE videos are becoming HOT and POPULAR - recently I have made this video http://www.hostinghosted.com/2011/12/31/hostgator/ Apple style videos are becoming popular day by day.
Simple i.e.
Background Color All white, Dress is simple business suite, Voice and Video quality is Super Quality.
This combination makes any ordinary style video into extra-ordinary.

If you TV show is targetting the Arab audience,

 

A long overcoat with long  skirt or dark colored pants. Avoid bright colors that might effect the news package with green screen (chroma key).