Meme of the week: Favourite Doctor Who companion

It may be dumb to give meme of the week a regular weekly slot on a Wednesday, but dumb’s my middle name and we can always argue that we’re trying to break down conventional definitions and concepts like ‘week’.

So to launch it in a blaze of glory/polite indifference (I’ll delete as applicable next week when we find out the state of play), since just about everyone here watches Doctor Who:

Who’s your favourite Doctor Who companion and why? And for the adventurous, who’s your least favourite/most hated?

Answers in the comments below or back at your own blog if you leave a link.