I would say, to start, you could go with two lights, umbrellas, and stands. For a portable studio, I would use AC powered lights. For a dedicated studio, lights that take a power supply would probably be better. They provide a faster recycle time and more consistent results. Regardless, focus more on features than on brand names. A lot of companies offer kits, so may want to look into something like that. In the end, just get the most you can for the money you have available. I hope this helps to some extent.

David Gewirtz is the author of How To Save Jobs and Where Have All The Emails Gone? For more than 20 years, he has analyzed current, historical, and emerging issues relating to technology, competitiveness, and policy. David is the Editor-in-Chief of the ZATZ magazines, is the Cyberterrorism Advisor for the International Association for Counterterrorism and Security Professionals, and is a member of the instructional faculty at the University of California, Berkeley extension. He can be reached at david@zatz.com and you can follow him at http://www.twitter.com/DavidGewirtz.