In response to a challenge from law professor and blogger Brad Smith, George Mason University legal scholar (and Reason contributor) Ilya Somin nominates a few of his candidates for "best Supreme Court decisions from a libertarian point of view":
Given my criteria, the Peonage Cases of the early 1900s surely rank high, as they enabled numerous southern blacks to escape a system of forced labor and did so at a time when Jim Crow racism was at its height, and the political branches of government showed little willingness to protect black rights. Also worthy Buchanan v. Warley (1917), which struck down racially based zoning, and helped prevent US state-imposed segregation from becoming as bad as that in South Africa under the Group Areas Act. Although it did not lead to much actual racial integration, Buchanan enabled blacks to move into many areas that would otherwise have been closed to them….
I also agree with Brad's nomination of Schechter Poultry v. United States (1935) , which invalidated the National Industrial Recovery Act, the most sweeping effort at economic central planning in all of American history. Enacted in 1933, the NRA cartelized nearly the entire nonagricultural economy; by raising prices and wages above market-clearing levels, it also increased unemployment and lowered industrial production at a time when both were already reeling from the Great Depression.
I'd second all of those, particularly Buchanan, which was argued and won by the great libertarian lawyer Moorfield Storey. And I'd add Lochner v. New York (1905), which upheld the right to liberty of contract, and District of Columbia v. Heller, which finally recognized that the Second Amendment secures an individual right to keep and bear arms. Hopefully by the end of the Court's current term we can add McDonald v. Chicago to the list as well.