For the first 2 Falloutgames it's mostly a question how you wan't to play but....
In Fallout 1&2 most the time (8 of 10) your skills decide if can or can't do something..persuading people is done with speech, charisma give you a barter&speechbonus and decides the basic attitude of the npcs toward you...
Int on the other hand decides the number of skillpoints/level and gives a bonus to several skills too.
The Fun with Falloutgames (esp. 2&New vegas) can play anything and a number of people even love the 1 Int brute idiot..playthough..but...if you plan to see as much possible, do as many quests as possible....a high Int is much more versatile then a high Cha
Edit:
If you wan't to know more about the SPECIAL-System for Fallout 1 take a look here
[url=http://fallout.wikia.com/wiki/Portal:Fallout]http://fallout.wikia.com/wiki/Portal:Fallout[/url]
Post edited March 24, 2018 by DF1871