I would recommend going with Guns as combat skill, for reasons of availability of both weapons and ammo.
As for S.P.E.C.I.A.L :
ST- 4+ Depending on which weapons you want to use and whether you're taking Weapons Handling.
PE- 6 for perk requirements
EN- 7, for maximum S.P.E.C.I.A.L implants
CH- Depends. If you plan to do all the fighting by yourself, you can strip it down to 1. If you want your followers to do more damage, leave it at 4-5.
IN-6+ Higher Intelligence means more skill points, but the usefulness of that is limited. You get about 0.5 skill point per level for each point in IN, so it's approximately 15 over the course of the game. You get four times that from the Educated perk, and with some planning of your skill point investment you can have all your skills maxed by level 30 with IN 6.
AG-6+. The more the better, but don't start off with 10.
LK- 6+ Again, the more the better but don't start off with 10. 6 is the minimum for perk requirements.
Traits- I would recommend Small Frame and either Trigger Discipline (if you plan to rely on automatic weapons) or Fast Shot (if you plan to rely on Cowboy or semi-auto guns).