In no particular order:
Reagan
Washington
Jefferson
Eisenhower
Lincoln
Coolidge
Kennedy (with reservations)
Nixon (also with reservations)
Those are all the presidents that come to mind right now. The Founding Fathers were some of the greatest men the world has ever known. Reagan was amazing for a whole slew of reasons. Coolidge was also amazing for actually putting the free market into practice. Eisenhower was a very effective leader. I don't think I need to talk about Lincoln. As for Kennedy, while he did some great things, I disagree with a number of social programs he supported. Nixon, by contrast, did some terrible things but was a genius at foreign policy and did help the country in some areas. Those are the only presidents I truly admire. I HATE both Roosevelts with every fiber of my being, along with Woodrow Wilson, some of the worst presidents we've ever had. The New Deal introduced social programs, yes, but they were hugely damaging to both the country itself and to the free market. Teddy Roosevelt, while he didn't get a chance to actually institute most of his ideas, shared some of these views with his cousin who would later be president too. Wilson's policies were the antithesis of everything America stood for, his boorish involvement in WWI and the later peace conferences certainly didn't do anything good for anyone, and he was a flaming racist, to boot.