George Washington was surely consequential; after all he set the precedent for every President who followed. He initiated the pattern for the Executive Branch and was instrumental in ratification of the United States Constitution and the Bill of Rights.
Thomas Jefferson was consequential, if only because with the Louisiana Purchase, he doubles the geographic size of the United States. His pre-presidential activities must also be considered.
Abraham Lincoln was consequential because he managed to hold the Union together during the Civil War and, of course, because he ended formal slavery in the United States of America. President Lincoln did the right things to place the care of America first.
Theodore Roosevelt (TR) was consequential because America became a recognized world power due to his actions such as initiating the construction of the Panama Canal. He was also the first President to recognize and take up the cause of working people who were being abused by the turn of the century “Robber Barons.” TR was the first modern President to fearlessly attack political corruption and do the right thing instead.
Because these four Presidents were recognized as being as consequential as they were, they have had their faces carved into Mount Rushmore in South Dakota, a beloved national monument.
Franklin D. Roosevelt was consequential because he was elected four times and because of his leadership during World War II.
Ronald Reagan was consequential because he was the first true political outsider to gain the White House and break the professional career politicians' hold on that position. Also, Reagan was the second President of the 20th century to attempt to fight professional politician corruption in Washington DC.