I wasn’t necessarily picking my favorite Vice Presidents. I think the person asked me to list the five most influential. Hobart is on the list because he was the most powerful Vice President until the modern reformation, of sorts, of the Vice Presidency. President McKinley and Garret Hobart were close and McKinley had great respect for Hobart (McKinley even turned to Hobart for personal financial advice and Hobart helped him invest his money). Hobart was invited to Cabinet meetings, which seems like normal activity now but it simply wasn’t until the mid-20th Century, and actively participated in the President’s Administration. There are questions about whether he actually attended the Cabinet meetings, but we know that he certainly advised the members of the Cabinet on various issues. He didn’t merely take a ceremonial role in presiding over the Senate, but helped push the McKinley Administration’s legislative agenda on Capitol Hill. In many ways, he acted much in the way as a modern White House Chief of Staff would.
Had Hobart not died in office in 1899, he may have continued to expand the relevance and power of the Vice Presidency and actually made the office into the significant position that it eventually became. Because of their close relationship and Hobart’s popularity nationally, I don’t think that there’s any doubt he would have remained on the ticket alongside McKinley in 1900 had he lived. If he had, he himself would have become President a year later when President McKinley was assassinated. Vice President Hobart’s death made it possible for Theodore Roosevelt to continue his rise (although the initial reasoning for making TR Vice President was to stymie his influence) and become President.