2. HK-47 - Knights of the Old Republic
BioWare's Knights of the Old Republic did an amazing job at creating an olden-days slant on the Star Wars universe, but every once in a while it got a little bit too pious for its own good. If you opted to follow the light side of The Force you were pretty much forced to play as a simpering goodie two-shoes, so when you stumbled across HK-47 in a robot shop on Tattooine, he was a breath of fresh air. Oh he seems nice enough the first time you chat to him, but as soon as you've paid for him he reveals his true identity as an electronic equivalent to Patrick Bateman. HK-47 is a natural born killer (or at least, a factory-made one) and he certainly loves his work. Aside from being very handy in a fight, he has a barbed sense of a humour and a habit of referring to humans as "meatbags". Both of these qualities went some way towards diluting KOTOR's squeaky clean morality.
1. Alyx Vance - Half Life 2 and Episodes
Gordon Freeman somehow manages to be one of those characters who attains greatness without ever actually saying anything, but at least part of his triumph must be attributed to Alyx Vance. As one of the first video game characters to successfully convey human emotion, Alyx plays a huge role in the dramatic rollercoaster that is Valve's master work. There's a memorable scene early in Half Life 2 in which, you, Alyx and the huge robot Dog all play together using the gravity gun; it's a quiet moment, but it's things like this that pay a huge dividend later on, when the three of you are fighting for your lives. In short, Alyx is the emotional heart of the Half Life series, and a strong contender for the best companion in contemporary gaming.
Who do you think are the best companions in video games? Let us know in the comments section below.