Off the top of my head, my favorite character was Tyvek, the bad-ass Rodian Gunslinger.
He was a stoic, surly but loyal goon to our ship’s captain (who was basically space Puss-in-Boots). At first he was kind of dull: quiet cool guy (not a lone wolf trope, though: he wanted company). But then I made him a space-cigar addict and a drunkard. Also, his astromech droid (like R2-D2) was a sarcastic jerk who always talked back to everyone and was sometimes deliberately obstinate to the rest of the crew.
Tyvek wore a poncho like the Man with No Name and often donned a cool black mask with glowing green goggle-eyes. The neat thing was that when the scene got tense, and he was getting ready for action (often at the secret code word of his captain), the goggle-eye lenses turned into a baleful red. Pretty cool…
Skill-wise, he was streetwise, stealthy and specialized in a single, huge pistol that looked a lot like a massively over-sized Magnum .356. Pretty cool.
I was really into Spaghetti Westerns at the time, and wanted to do something interesting with my character choice for a Star Wars (D20) campaign that we were running. Luckily our theme was basically Firefly: a rag-tag crew of scoundrels hopping around the galaxy up to no good.
The problem with Rodians is that they have these big bug eyes without eyelids. How on earth could I imitate the Clint Eastwood squint? Easy: I specified in Tyvek’s background that he hailed from a harsh desert planet with lots of sandstorms (no, not Tatooine). So I explained how he had acquired eyelids through plastic surgery so as to protect himself from the sandy atmosphere and from the glaring sun.
Yes, Tyvek is stolen from the brand name of industrial building material. I just thought that it sounded really cool.