Farm Accident Digest offers a Geek Test in which one is categorized by which item upsets you the most. I am solidly in the first group: Greedo shoots first. Han Solo is a man used to living in a criminal underworld. It is that type of sensibility that makes his evolution into a hero so much more impressive than Luke's.
Besides, when the guy holding a blaster on me says that he might not deliver me for the bounty because he would enjoy killing me himself, I'd take that as a green light to open fire.