For interviews, Kinoflos or Cool Lights equivalent are a very useful tool as you can bulb them with daylight or tungsten. A 4-bank makes a good key. For fill, use foamcore or showcard (best to grip with a c-stand). Add a small backlight either hung from the ceiling or flown on a c-stand. So with two lights you can have basic 3-point lighting. The backlight can by a 2x2 kino or equivalent, or any number of small tungsten units with 1/2 CTO when shooting in daylight situations.
After that, many, many more additions and substitutions. Read Lighting for Motion Pictures and Television by Blain Brown, or a shorter and simpler book, Video Shooter by Braverman, or John Jackman's Lighting for Digital Video and Television.
Rick Thank you very much, my budget for a lighting set is just about $ 1800 and i intend to buy them from BHPHOTO.com, because of this low budget i don't want to make any mistakes with my choice, can you recommend a specific light set within this range, as most of my interviews are conducted indoors and i want to get a perfect color tone.
If I was buying, I'd look at the Lowell Omni core 44 set or DV Core 500 set at the B*H site.
Or, I'd get the Rifa eX-88, with the switchable flo/tungsten bulb head, a Lowel Omni, and some extra stands and relfectors and scrims, etc.
Then again, I'm an unabashed Lowel fanboy.
Smith-Victor makes an inexpensive softbox for under $200.
For indoor interview setups, I really like a large sofbox for the key, a bounce card stealing some of the spill of the softbox for usea as a free fill, and a small instrument or two for backlight/hairlight (if desired) and something to play on the walls behind with.