I have the following list of builds for F1, F2, F3, and NV:

F1 and F2:

Sniper (targeted shots with single shot weapons)
Quickshot (single shot weapons with Fast Shot)
Burst Fire Big Guns (uses miniguns and heavy machineguns)
Burst Fire Energy Weapons (uses Gatling Laser)
Pyromaniac (uses Flamer)
Hand To Hand (fights with unarmed and melee weapons)
Quickfist (uses Fast Shot with unarmed and melee weapons. F1 only as Fast Shot doesn't affect Hth attacks in F2)
Jinxed (hand to hand with Jinxed)

F3

Critical (high critical chance. Attacks mainly out of stealth)
Assassin (same, but mostly relies on sneak attack criticals)
Low Critical (high dps without criticals)
Pyromaniac (uses fire weapons)

NV

Critical (focuses on critical hit and damage as often as possible. Uses weapons with high critical chance modifiers together with high damage per shot and critical damage.)

-Cowboy
-Cowboy Shotgun
-Grunt
-Guns
-Shotgun
-Laser
-Plasma
-Hand To Hand
-Pyro Hand To Hand

Automatic Critical (combines Light Touch and automatic weapons)
-Grunt
-Guns
-Laser
-Plasma

Quickshot (increased attack speed with critical hits. Weapons with fast attack speed are best used, together with good critical chance and damage)

-Cowboy
-Cowboy Shotgun
-Grunt
-Guns
-Shotgun
-Laser
-Plasma
-Hand To Hand
-Pyro Hand To Hand

All Out (high damage without criticals, high dps. Uses automatic ranged weapons or hard hitting hand to hand weapons)

-Grunt
-Guns
-Laser
-Plasma
-Hand To Hand
-Pyromaniac
-Demolitionist

All builds in Fallout 1 and 2 have the option of whether or not to be either Gifted or Stupid.

All builds in F3 can be built whether or not they will use either or both VATS and Almost Perfect.

All builds in New Vegas have the option of whether or not to use VATS. All critical or quickshot builds have variants for whether or not to use Light Touch and VATS.

I haven't put together anything for Fallout Tactics due to that game being more complicated.

In F3, it's easy due to the low perk rate and near lack of specialization perks to specialize in all combat styles.

Obviously, it's easier to specialize in NV due to all the specialization perks, including Laser Commander, Shotgun Surgeon, Plasma Spaz, Piercing Strike. There are also perks for using Light Armor. Obviously, the perks you choose limit your endgame playstyle and combat style.

In F1 and F2, there really aren't all that many specialty perks for specific combat styles, such as Energy Weapons, Small Guns, etc. So there's really no point to stick with either Small Guns or Melee weapons solely throughout the whole game. You need to choose ranged or hand to hand and stick with it.