Journalists and almost any category of "entertainer" need a visa. I also know someone who works in the defence industry here in the UK who has a visa because of his position.
Yes the visa required is a B-1 visa. It's required if you are a non resident on business for a temporary period of time. Up to 90 days I believe but I stand to be corrected on this. If you intend to be a permanent immigrant on business/working in the US there is another Visa required but i can't remember which one it is.
If you are a tourist however, the ESTA essentially waivers you on unless
1) you've been 'naughty'
and have a police file/record that doesn't flatter your character or
2) if you've outstayed your welcome in the USA previously.