7. Boris Johnson
Although Boris Johnson isn't exactly massively well known in the United States of America, if he was to voice himself in an episode in which the Simpson family came to London, I'm sure it would go down well with everyone. British audiences would love it, for starters, but he's the kind of bumbling, stereotypical upper-class toff from across the pond that American animated sitcoms tend to create and enjoy anyway. Non-Brits might find him quite hard to understand (Arnold Schwarzenegger famously said "this guy is fumbling all over the place" in reference to a fairly nonsensical speech Boris gave), but that would add to the humour - and just imagining what the Simpsons-style drawing of him would look like is making me laugh as I type this.