If you are interested in working in a regulatory area of law (antitrust, securities, food & drug, communications, the list goes on...) you may actually be better served by working in an agency, especially at the federal level in Washington, DC or at, for instance, a DOJ field office. Obviously this won't work for everyone due to location, but the best regulatory attorneys I know worked at the respective agency(ies) fairly early in their careers, then 10-15 years in private practice, then went back to an agency in a senior position. They don't call it a revolving door for nothing.