Based on various historians' polls and public opinion surveys over the years, here are ten presidents often ranked among the best and worst:

Often Ranked Among the Best (not in a specific order)

1. George Washington: The first U.S. president, he set many critical precedents for the role.

2. Abraham Lincoln: Preserved the Union during the Civil War and signed the Emancipation Proclamation.

3. Franklin D. Roosevelt: Guided the U.S. through the Great Depression and most of World War II.

4. Theodore Roosevelt: Known for progressive reforms and conservation efforts.

5. Thomas Jefferson: Author of the Declaration of Independence and overseer of the Louisiana Purchase.

6. Harry S. Truman: Made the controversial decision to drop atomic bombs on Japan and oversaw the beginning of the Cold War era.

7. Dwight D. Eisenhower: Managed the U.S. during a period of relative peace and prosperity in the 1950s.

8. James Madison: Known as the "Father of the Constitution" and led the U.S. during the War of 1812.

9. John F. Kennedy: Inspiring leader who faced the Cuban Missile Crisis but was assassinated after only 1,000 days in office.

10. Ronald Reagan: Former actor and governor, credited with a strong economy and ending the Cold War.

Often Ranked Among the Worst or Most Controversial (not in a specific order)

1. James Buchanan: Seen as failing to prevent the Civil War.

2. Andrew Johnson: Mishandled post-Civil War Reconstruction and narrowly escaped impeachment.

3. Warren G. Harding: Marred by corruption scandals like Teapot Dome.

4. Franklin Pierce: His policies, such as the Kansas-Nebraska Act, inflamed sectional tensions.

5. Richard Nixon: Only president to resign from office due to the Watergate scandal.

6. John Tyler: Often criticized for his annexation of Texas and setting the stage for sectional conflicts.

7. Millard Fillmore: Supported the controversial Compromise of 1850 and the Fugitive Slave Act.

8. Martin Van Buren: His tenure was marked by an economic depression, the Panic of 1837.

9. Herbert Hoover: Struggled with the Great Depression's onset, often seen as ineffective in combating it.

10. Zachary Taylor: His short tenure and lack of clear policy direction often leads to low rankings.

Again, these rankings are not definitive. For more recent presidents, legacies are still being shaped by ongoing events and evolving historical perspectives.