I'd have to say I actually like the word 'favorite'. I also like the words 'color', 'rumor', 'labor', 'humor' and 'honor'. I like them because they have just the right amount of letters in them without any superfluous vowels. I also like words such as 'center' and 'theater', because they're spelled just like they're more or less pronounced.
Of course 'fuck' has to be the king. Not for its vulgarity, but for the pure utility of the word. It can be used as used as just about any form of word possible, which is a fucking win to me.