Science fiction is full of brilliant ideas — but it's also the home of some fascinating characters. And the British Film Institute is trying to find the greatest science fiction character of all time — but I bet we can do even better, right here. Who are the greatest characters in all of science fiction?

Please post a picture or clip (or book cover) for your chosen character. And please mention his/her name, and where he/she appears. And if someone else has already posted a particular character, you should just star the existing post. Thanks!

Top image: Ripley, from the Alien movies. No question.