Let's take them all...
Charles Fairbanks (1905-9): Would probably have delayed the Progressive Era slightly, but after TR there was no turning back.
James Sherman (1909-13): Would have died in office just before the 1912 election, further ensuring a Wilson or Clark victory.
Thomas Marshall (1913-21): Should have been POTUS, Wilson was clearly incapacitated and what we'd later call a picture-perfect 25th case.
Calvin Coolidge (1921-3): Became POTUS IOTL.
Charles Dawes (1925-9): Would have tried and renegotiated German reparations, involved the US more in international affairs. Continuation of Coolidge's domestic policies.
Charles Curtis (1929-33): Not much different from Hoover, would have tried a 5-day work week with no wage reduction to combat the GD. Loses to FDR in a landslide, as would any Republican, in 1932.
Jack Garner (1933-41): Would have seriously compromised the possibility of US recovery from the GD, and little chance of US entering WWII unless a liberal Republican wins in 1940. There would not be a
Man in the High Castle ASB scenario.
Henry Wallace (1941-5): Why not put Alger Hiss in the Oval Office and get it over with? Heaven help the US if he become POTUS. Harry Dexter White as Secretary of the Treasury, Alger Hiss as Secretary of State: two Soviet spies as the ranking Cabinet officers of the US government!

Harry Truman (1945): Became POTUS IOTL.
Alben Barkley (1949-53): Similar to Truman, would enact New Deal, but might not push Marshall Plan and Truman Doctrine as firmly as Truman.
Richard Nixon (1953-61): Became POTUS IOTL, but would be much more of a doctrinaire Cold Warrior than OTL.
Lyndon Johnson (1961-3): Became POTUS IOTL, but he was the VP in name only.
Hubert Humphrey (1965-9): Would be LBJ's clone, as proven in the 1968 primaries IOTL.
Spiro Agnew (1969-73): See Drew's
Fear, Loathing and Gumbo.
Gerald Ford: (1973-4): Became POTUS IOTL.
Nelson Rockefeller (1974-7): Would be an excellent POTUS, but would not run in 1976 re age and health.
Walter Mondale (1977-81): A Humphrey New Dealer, on the liberal wing of the Democratic Party. Would not be a DLC moderate like Carter, but with much better Congressional relations, being an insider.
George H.W. Bush (1981-9): Became POTUS IOTL.
Dan Quayle (1989-93): Heaven help the US: the male Palin presiding over the end of the Cold War!
Al Gore (1993-2001): A Clinton clone, would be a good President.
Dick Cheney (2001-09): No Comment.
Joe Biden (2009-present): Gaffe-prone, but a more effective POTUS than Obama.