At the risk of sounding ridiculous - Charles Kennedy may be the most influential politician on me personally so far.
Kennedy had a relaxed charisma, a trustworthiness. It was he who got me interested in politics, and as a matter of fact, I partially voted Lib Dem in 2010 on the back of the belief in that party that I was given by Kennedy, who got their best ever result at the '05 election (a result that under other electoral systems would've got his party something like 25% of the seats in the Commons).
He seemed to me to be a man of honour, he was pretty funny, and - and this is a somewhat farcical measure, but sadly now part of the political landscape - always good fun on Have I Got News For You.
I respected Charles Kennedy a great deal, always hated the media's jokes about his alcoholism and his loss at such a young age is truly tragic.
And in fact, it was my loyalty to Kennedy that made it such a personal slight when the Lib Dems steadily exposed themselves as being as bad as other politicians over the previous five years (although I'm even revising that viewpoint but that's a discussion for another thread).