d20 Modern / d20 Future because it is customizable to what you want. I know a lot of people have issue with the system, but I personally love it. I think you can do just about anything with it. I've actually got an old Firefly character from BIG DAMN HEROES - a d20 Firefly Campaign...I'll post him below. You can take a look and see if it fits the sort of feel you want for PCs in your game:
Patrick “Win” Winslow
Patrick Winslow, or simply “Win” as he is called by companions, hails from Dyton Colony, a son of a fairly prominent landowner. Although his family had more money than most, Patrick never cared much for a life of finery. Adventure and excitement, that was the thing. Patrick learned to fight and shoot, getting in more than his fair share of trouble as a youngster. When the Unification War started, he volunteered immediately, and fought for the Independents until the war's end. Since the end of the war, Win has wondered the ‘Verse, keeping mostly to the Rim and Border worlds, making a living at what jobs he can get. Between his travels and service with the Browncoats, he has picked up a hodgepodge of skills that have given him some success in finding work.
Win is a broad-shouldered, muscular man standing just over six feet in height. He wears his brown hair cropped close in the military style, and often sports a very fine goatee. While he might otherwise be a handsome man, Win bears a fierce looking scar that runs from his forehead, across the right eye and down his cheek. If asked about it, he states simply that it was a souvenir from the war. He dresses in simple, practical garb, and is seemingly never without a gun.
Win is a good man, and tries to do the right thing, though life in the Black sometimes makes that difficult. He's no low-down, dirty deceiver, and in fact, has a hard time with telling lies. Because of the work he does and the type of folk he deals with, he usually chooses to say nothing at all. Give him a few drinks, though, and it is hard to shut him up.
Fast 2 / Strong 4 - Adventurer
STR 14 (6 points)
DEX 17 (10 points, +1 level increase)
CON 14 (6 points)
INT 14 (6 points)
WIS 10 (2 points)
CHA 10 (2 points)
Init +7 (+3 dex +4 feat)
HD: 8 + 29 (5d8) +12 = 49
Roll Lookup
DEF 25 (+7 class, +3 dex, +5 armor)
Speed: 35’
BAB +5
Melee +7
Ranged +8
REP +1 (+0 class +1 trait)
Action Points: 9
FORT +4 (2 base + 2 con)
REF +6 (3 base + 3 dex)
WIL +1 (1 base + 0 wis)
Attacks
Hvy Auto Loader +9, +10 within 30’ (2d8; 40 ft; S; 9 box)
Unarmed +9 (1d8+4 non-lethal)
Whip +7 (1d2+2; 15 ft)
FEATS
Personal Firearms Proficiency – Rim Homeworld
Brawl - Occupation
Armor Proficiency (Light) – Lvl 1
Improved Initiative – Lvl 1
Simple Weapons Proficiency – Lvl 1 Fast
Point Blank Shot - Lvl 2 Fast Bonus
Weapon Focus (Hvy Auto Loader) – Lvl 2 Strong Bonus
Armor Proficiency (Medium) – Lvl 3
Double Tap - Lvl 5
Improved Brawl - Lvl 4 Strong Bonus
TALENTS
Increased Speed
Melee Smash
Improved Melee Smash
TRAITS
Saddleborn
Distinctive
SKILLS 35 + 20
Balance +4 (5 ranks, +3 dex, -4 armor)
Climb +1 (3 ranks, +2 str, -4 armor)
Drive +5 (2 ranks, +3 dex)
Handle Animals -1 (0 ranks, +0 cha, -1 trait)
Hide +3 (4 ranks, +3 dex, -4 armor)
Jump +1 (3 ranks, +2 str, -4 armor)
Knowledge - Tactics +5 (3 ranks, +2 int)
Move Silently* +5 (5 ranks, +3 dex, +1 competence, -4 armor)
Pilot +7 (4 ranks, +3 dex)
Profession +1 (1 rank, +0 wis)
Repair* +8 (7 ranks, +1 int)
Ride +8 (4 ranks, +3 dex, +1 trait)
Spot* +7 (7 ranks, +0 wis)
Survival* +5 (5 ranks, +0 wis)
Swim +4 (2 ranks, +2 str)
EQUIPMENT
Range pack, standard
Bolt Cutter
Duct Tape, 2 rolls
Compass
Flashlight, standard
Binoculars, standard
Walkie-talkie, basic
4 ammo magazines
Illuminator
Holster, hip
Knife
Whip
Ammo, heavy auto loader (150 rounds)
Light Duty Vest (DC17, reduced wealth to 5)
Heavy Autoloader - PK12 Peacekeeper (DC19, reduced wealth to 2)
Current Wealth: 2 (Starting 7)
