Thanks for the info, I currently only use 1 playthrough, and im not really trying to role-play, I'm trying to find out the skills that are used more throughout the game
OK. That's cool. It's still gonna depend on your playstyle quite a bit. IMO the most important non-combat skills are, in this order: Repair, Speech, Lockpick, Science. Science goes up if you're playing an energy weapons contric character. Repair is even more important for a guns character. Sneak, I consider a combat skill, but that depends on playstyle. Playing a sniper? High sneak. Playing a ninja or assasin? High sneak. Otherwise, don't worry about it, unless you wanna take a minigun into the casinos. hardcoe players will get the most from Survival, and medicine can be a helpful skill for all builds too. You can leave Barter at beginning levels and still become richer than Bill Gates, but there are a few perks that need it and some end game skill checks it helps too.
All of this is moot though, if you dl all the dlcs. With a cap of 50, it doesn't take much to max all your skills even with a 1 IN. What may help you some would be to look at http://fallout.wikia.com/wiki/Fallout:_New_Vegas_perks, figure out which perks you really, really want, and make sure you get to the required skill level for them.
Give us a little more info on your playstyle/build and we could be more specific.
-gunny