My most successful build up till now, Dexterity Pistol-Knife build (at lvl 20):
Base:
STR 5
DEX 12
AGI 6
CON 4 (5)
PER 10
WIL 3
INT 5
Skills:
Guns 110
(166)Throwing 25
(42)Melee 110
(184)Dodge 35
(43)Evasion 35
(43)Lockpicking 70
(117)Traps 10
(34)Mechanics 110
(119)Electronics 110
(119)Chemistry 10
(15)Biology 55
(60)Tailoring 110
(119)Persuasion 70
(66)Mercantile 20
(35)Feats:
Aimed Shot
Opportunist
Pack Rathound (not really necessary but I am a hoarder so I need this)
Sprint
Steadfast Aim
Doctor
Dirty Kick (can be replaced by a Taser)
Execute
Cheap Shots
Expose Weakness
Sharpshooter
(Also works good with Taste For Blood (requires different knife type), Nimble or Kneecap Shot)
Equipment (core):
Seeker Goggles
High Frequency Shield
Riot Armor with Burrower Shield
Bullet Strap Belt
.44 Hammerer
Dagger (preferable Tungsten or TiChrome)
PigLeather Tabi
With this build you can shoot 2 times with the .44 in one turn (because of AP reduction) doing massive damage (especially if it crits or when using execute). Besides from that you have moderate amount of defense and above average movement points. The knife attacks quite strong too because of the high crit chance/damage, you can even take down medium-heavy armored opponents with the knife!
You can also spot most traps (high PER + traps)
Choose for SGS in the Junkyard and access to some other quests (persuasion)
Craft high quality weapons, amour, shields etc (Mechanics, Electronics, Tailoring)
Able to craft all medicine and mining TNT (Biology, Chemistry)
Also a fun build is pure strength (15 points at lvl20) sledgehammer mayhem + ice. I can shatter most enemy's when they at 300hp, its really fun