I believe that the media is not very reliable in conveying the truth although it is a very powerful tool in disseminating information to the people of that particular country and worldwide. It plays a very significant role in the people's understanding and stand on current issues which may directly affect them.
If the media fabricate lies and attempt to cover up actual information to delude the people, it would have very serious consequences, people may accept the lies as truth, they would blindly support something which is internationally-preceived as incorrect, leading to misunderstandings. Take for example, in North Korea where the communist government has a firm grip on the media, people are unable to understand the world's concern over their country's nuclear enrichment. In some other cases, it can be dangerous, such as the cover up of outbreak of diseases. An example would be the recent case of bird flu, if the country does not acknowledge of such an outbreak and use the media to provide the general public with full accurate information, it would have disastrous consequences.
To a certain extent, I feel that the media indeed would portray the truth, only if it does not affect the ruling party. Some typical examples would be some natural disaster which happened in some other country or some social problem faced globally, information which is objective. Different countries have different extent of control on the media, the media is thus credible to varying degrees.