What are the three most important legacies of the jeffersonian presidency?

The Louisana Purchase was the single greatest legacy, and while the manner in which it was achieved was surely not in compliance with the US Constitution, it was a valuable contribution. Jefferson as an individual and as a President was always intered in scientific discovery and in education. Another area that remains relevant today is his support for an armed citizen, and his insistence on freedom from religion and of religion. States rights versus Federal, a smaller, leaner Federal government, a contempt for banks and corporations. Anything dealing with Jefferson as President or his legacy as President must begin the Louisiana Purchace, the second and third spots are a matter of personal preference.