Strength - 5 is good
Perception - 4 or 5
Endurance - up to 9 is awesome. If you have less than 9, you can't get all the implants in the game.
Charisma - 4 or 5. Pretty useless.
Intelligence - up to 9. Not as important as in FO1 or FO2, but still useful.
Agility - not really sure, but above...